Class 10 Science Chemical Reactions and Equations Important Formulas
Important Formulas for Class 10 Science Chemical Reactions and Equations. Try first, then reveal the answer. These are exam-oriented practice items, not copied board papers.
Practice questions aligned to NCERT topics used in CBSE classrooms. These are original exam-oriented questions for revision — not official CBSE board papers and not a guarantee of any exam question. Always match the textbook issued by your school and the latest PDFs on ncert.nic.in and cbseacademic.nic.in.
Balanced equation. A balanced chemical equation has the same number of atoms of each element on both sides.
Combination reaction. In a combination reaction two or more substances join to form a single product.
Decomposition. A decomposition reaction splits one compound into two or more products, often with heat, light or electricity.
Displacement. A more reactive metal can displace a less reactive metal from its salt solution.
Redox. Oxidation and reduction occur together in a redox reaction.
Exothermic. An exothermic reaction releases heat to the surroundings.
Endothermic. An endothermic reaction absorbs heat from the surroundings.
Precipitation. A precipitate is an insoluble solid formed in a double-displacement reaction.
Chemical Reactions and Equations. A chemical equation must be balanced for mass.
Chemical Reactions and Equations. Combination, decomposition, displacement, double displacement.
Redox. Redox: oxidation is gain of oxygen or loss of electrons as taught.
Chemical Reactions and Equations. Exothermic vs endothermic.
Chemical Reactions and Equations. Precipitation reactions.
Practice set
Q1MCQ1 markEasyRevision pick
Choose the correct statement related to Balanced equation in the chapter Chemical Reactions and Equations.
A. An exothermic reaction releases heat to the surroundings
B. A decomposition reaction splits one compound into two or more products, often with heat, light or electricity
C. Mass need not be conserved
D. A balanced chemical equation has the same number of atoms of each element on both sides
Answer
D. A balanced chemical equation has the same number of atoms of each element on both sides
Explanation
A balanced chemical equation has the same number of atoms of each element on both sides. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q2MCQ1 markEasy
Choose the correct statement related to Combination reaction in the chapter Chemical Reactions and Equations.
A. In a combination reaction two or more substances join to form a single product
B. A more reactive metal can displace a less reactive metal from its salt solution
C. An endothermic reaction absorbs heat from the surroundings
D. Combination, decomposition, displacement, double displacement
Answer
A. In a combination reaction two or more substances join to form a single product
Explanation
In a combination reaction two or more substances join to form a single product. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q3MCQ1 markEasy
Choose the correct statement related to Decomposition in the chapter Chemical Reactions and Equations.
A. A precipitate is an insoluble solid formed in a double-displacement reaction
B. A decomposition reaction splits one compound into two or more products, often with heat, light or electricity
C. Oxidation and reduction occur together in a redox reaction
D. Redox: oxidation is gain of oxygen or loss of electrons as taught
Answer
B. A decomposition reaction splits one compound into two or more products, often with heat, light or electricity
Explanation
A decomposition reaction splits one compound into two or more products, often with heat, light or electricity. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q4MCQ1 markEasy
Choose the correct statement related to Displacement in the chapter Chemical Reactions and Equations.
A. A more reactive metal can displace a less reactive metal from its salt solution
B. An exothermic reaction releases heat to the surroundings
C. Exothermic vs endothermic
D. A chemical equation must be balanced for mass
Answer
A. A more reactive metal can displace a less reactive metal from its salt solution
Explanation
A more reactive metal can displace a less reactive metal from its salt solution. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q5MCQ1 markModerateRevision pick
Choose the correct statement related to Redox in the chapter Chemical Reactions and Equations.
A. Combination, decomposition, displacement, double displacement
B. Precipitation reactions
C. Oxidation and reduction occur together in a redox reaction
D. An endothermic reaction absorbs heat from the surroundings
Answer
C. Oxidation and reduction occur together in a redox reaction
Explanation
Oxidation and reduction occur together in a redox reaction. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q6MCQ1 markEasy
Choose the correct statement related to Exothermic in the chapter Chemical Reactions and Equations.
A. Redox: oxidation is gain of oxygen or loss of electrons as taught
B. A precipitate is an insoluble solid formed in a double-displacement reaction
C. This idea is not part of the NCERT chapter
D. An exothermic reaction releases heat to the surroundings
Answer
D. An exothermic reaction releases heat to the surroundings
Explanation
An exothermic reaction releases heat to the surroundings. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q7MCQ1 markEasy
Choose the correct statement related to Endothermic in the chapter Chemical Reactions and Equations.
A. An endothermic reaction absorbs heat from the surroundings
B. The textbook says the opposite of this statement
C. A chemical equation must be balanced for mass
D. Exothermic vs endothermic
Answer
A. An endothermic reaction absorbs heat from the surroundings
Explanation
An endothermic reaction absorbs heat from the surroundings. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q8MCQ1 markEasy
Choose the correct statement related to Precipitation in the chapter Chemical Reactions and Equations.
A. Precipitation reactions
B. This happens only in a laboratory and never in daily life
C. A precipitate is an insoluble solid formed in a double-displacement reaction
D. Combination, decomposition, displacement, double displacement
Answer
C. A precipitate is an insoluble solid formed in a double-displacement reaction
Explanation
A precipitate is an insoluble solid formed in a double-displacement reaction. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q9MCQ1 markEasyRevision pick
Choose the correct statement related to Chemical Reactions and Equations in the chapter Chemical Reactions and Equations.
A. A chemical equation must be balanced for mass
B. A balanced chemical equation has the same number of atoms of each element on both sides
C. Redox: oxidation is gain of oxygen or loss of electrons as taught
D. This idea is not part of the NCERT chapter
Answer
A. A chemical equation must be balanced for mass
Explanation
A chemical equation must be balanced for mass. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q10MCQ1 markModerate
Choose the correct statement related to Chemical Reactions and Equations in the chapter Chemical Reactions and Equations.
A. The textbook says the opposite of this statement
B. Combination, decomposition, displacement, double displacement
C. In a combination reaction two or more substances join to form a single product
D. Exothermic vs endothermic
Answer
B. Combination, decomposition, displacement, double displacement
Explanation
Combination, decomposition, displacement, double displacement. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q11MCQ1 markEasy
Choose the correct statement related to Redox in the chapter Chemical Reactions and Equations.
A. Precipitation reactions
B. Redox: oxidation is gain of oxygen or loss of electrons as taught
C. A decomposition reaction splits one compound into two or more products, often with heat, light or electricity
D. This happens only in a laboratory and never in daily life
Answer
B. Redox: oxidation is gain of oxygen or loss of electrons as taught
Explanation
Redox: oxidation is gain of oxygen or loss of electrons as taught. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q12MCQ1 markEasy
Choose the correct statement related to Chemical Reactions and Equations in the chapter Chemical Reactions and Equations.
A. A more reactive metal can displace a less reactive metal from its salt solution
B. This idea is not part of the NCERT chapter
C. A balanced chemical equation has the same number of atoms of each element on both sides
D. Exothermic vs endothermic
Answer
D. Exothermic vs endothermic
Explanation
Exothermic vs endothermic. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q13MCQ1 markEasyRevision pick
Choose the correct statement related to Chemical Reactions and Equations in the chapter Chemical Reactions and Equations.
A. In a combination reaction two or more substances join to form a single product
B. The textbook says the opposite of this statement
C. Oxidation and reduction occur together in a redox reaction
D. Precipitation reactions
Answer
D. Precipitation reactions
Explanation
Precipitation reactions. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q14MCQ1 markEasy
Choose the correct statement related to Balanced equation in the chapter Chemical Reactions and Equations.
A. Precipitation reactions
B. This happens only in a laboratory and never in daily life
C. A balanced chemical equation has the same number of atoms of each element on both sides
D. A skeleton equation is already balanced
Answer
C. A balanced chemical equation has the same number of atoms of each element on both sides
Explanation
A balanced chemical equation has the same number of atoms of each element on both sides. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q15MCQ1 markModerate
Choose the correct statement related to Combination reaction in the chapter Chemical Reactions and Equations.
A. A precipitate is an insoluble solid formed in a double-displacement reaction
B. Oxidation and reduction occur together in a redox reaction
C. In a combination reaction two or more substances join to form a single product
D. A balanced chemical equation has the same number of atoms of each element on both sides
Answer
C. In a combination reaction two or more substances join to form a single product
Explanation
In a combination reaction two or more substances join to form a single product. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q16MCQ1 markEasy
Choose the correct statement related to Decomposition in the chapter Chemical Reactions and Equations.
A. In a combination reaction two or more substances join to form a single product
B. An exothermic reaction releases heat to the surroundings
C. A chemical equation must be balanced for mass
D. A decomposition reaction splits one compound into two or more products, often with heat, light or electricity
Answer
D. A decomposition reaction splits one compound into two or more products, often with heat, light or electricity
Explanation
A decomposition reaction splits one compound into two or more products, often with heat, light or electricity. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q17MCQ1 markEasyRevision pick
Choose the correct statement related to Displacement in the chapter Chemical Reactions and Equations.
A. A decomposition reaction splits one compound into two or more products, often with heat, light or electricity
B. A more reactive metal can displace a less reactive metal from its salt solution
C. Combination, decomposition, displacement, double displacement
D. An endothermic reaction absorbs heat from the surroundings
Answer
B. A more reactive metal can displace a less reactive metal from its salt solution
Explanation
A more reactive metal can displace a less reactive metal from its salt solution. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q18MCQ1 markEasy
Choose the correct statement related to Redox in the chapter Chemical Reactions and Equations.
A. A precipitate is an insoluble solid formed in a double-displacement reaction
B. Redox: oxidation is gain of oxygen or loss of electrons as taught
C. Oxidation and reduction occur together in a redox reaction
D. A more reactive metal can displace a less reactive metal from its salt solution
Answer
C. Oxidation and reduction occur together in a redox reaction
Explanation
Oxidation and reduction occur together in a redox reaction. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q19MCQ1 markEasy
Choose the correct statement related to Exothermic in the chapter Chemical Reactions and Equations.
A. Oxidation and reduction occur together in a redox reaction
B. A chemical equation must be balanced for mass
C. Exothermic vs endothermic
D. An exothermic reaction releases heat to the surroundings
Answer
D. An exothermic reaction releases heat to the surroundings
Explanation
An exothermic reaction releases heat to the surroundings. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q20MCQ1 markModerate
Choose the correct statement related to Endothermic in the chapter Chemical Reactions and Equations.
A. An endothermic reaction absorbs heat from the surroundings
B. Precipitation reactions
C. An exothermic reaction releases heat to the surroundings
D. Combination, decomposition, displacement, double displacement
Answer
A. An endothermic reaction absorbs heat from the surroundings
Explanation
An endothermic reaction absorbs heat from the surroundings. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q211 Mark1 markEasy
Define or state: Precipitation.
Answer
A precipitate is an insoluble solid formed in a double-displacement reaction.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q221 Mark1 markEasy
Define or state: Chemical Reactions and Equations.
Answer
A chemical equation must be balanced for mass.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q231 Mark1 markEasy
Define or state: Chemical Reactions and Equations.
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q241 Mark1 markEasy
Define or state: Redox.
Answer
Redox: oxidation is gain of oxygen or loss of electrons as taught.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q251 Mark1 markModerate
Define or state: Chemical Reactions and Equations.
Answer
Exothermic vs endothermic.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q261 Mark1 markEasy
Define or state: Chemical Reactions and Equations.
Answer
Precipitation reactions.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q271 Mark1 markEasy
Define or state: Balanced equation.
Answer
A balanced chemical equation has the same number of atoms of each element on both sides.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q281 Mark1 markEasy
Define or state: Combination reaction.
Answer
In a combination reaction two or more substances join to form a single product.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q291 Mark1 markEasy
Define or state: Decomposition.
Answer
A decomposition reaction splits one compound into two or more products, often with heat, light or electricity.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q301 Mark1 markModerate
Define or state: Displacement.
Answer
A more reactive metal can displace a less reactive metal from its salt solution.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q312 Mark2 marksModerate
Give two points to explain Redox as used in Chemical Reactions and Equations.
Answer
1. Oxidation and reduction occur together in a redox reaction.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q322 Mark2 marksDifficult
Give two points to explain Exothermic as used in Chemical Reactions and Equations.
Answer
1. An exothermic reaction releases heat to the surroundings.
2. Respiration and many combustions
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q332 Mark2 marksModerate
Give two points to explain Endothermic as used in Chemical Reactions and Equations.
Answer
1. An endothermic reaction absorbs heat from the surroundings.
2. Photosynthesis
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q342 Mark2 marksModerate
Give two points to explain Precipitation as used in Chemical Reactions and Equations.
Answer
1. A precipitate is an insoluble solid formed in a double-displacement reaction.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q352 Mark2 marksModerate
Give two points to explain Chemical Reactions and Equations as used in Chemical Reactions and Equations.
Answer
1. A chemical equation must be balanced for mass.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q362 Mark2 marksDifficult
Give two points to explain Chemical Reactions and Equations as used in Chemical Reactions and Equations.
Answer
1. Combination, decomposition, displacement, double displacement.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q372 Mark2 marksModerate
Give two points to explain Redox as used in Chemical Reactions and Equations.
Answer
1. Redox: oxidation is gain of oxygen or loss of electrons as taught.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q382 Mark2 marksModerate
Give two points to explain Chemical Reactions and Equations as used in Chemical Reactions and Equations.
Answer
1. Exothermic vs endothermic.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q392 Mark2 marksModerate
Give two points to explain Chemical Reactions and Equations as used in Chemical Reactions and Equations.
Answer
1. Precipitation reactions.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q402 Mark2 marksDifficult
Give two points to explain Balanced equation as used in Chemical Reactions and Equations.
Answer
1. A balanced chemical equation has the same number of atoms of each element on both sides.
2. 2H2 + O2 → 2H2O
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q413 Mark3 marksModerateRevision pick
Explain Combination reaction in about three points, with one example.
Answer
In a combination reaction two or more substances join to form a single product. Example: CaO + H2O → Ca(OH)2
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q423 Mark3 marksModerate
Explain Decomposition in about three points, with one example.
Answer
A decomposition reaction splits one compound into two or more products, often with heat, light or electricity. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q433 Mark3 marksModerate
Explain Displacement in about three points, with one example.
Answer
A more reactive metal can displace a less reactive metal from its salt solution. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q443 Mark3 marksDifficult
Explain Redox in about three points, with one example.
Answer
Oxidation and reduction occur together in a redox reaction. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q453 Mark3 marksModerateRevision pick
Explain Exothermic in about three points, with one example.
Answer
An exothermic reaction releases heat to the surroundings. Example: Respiration and many combustions
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q463 Mark3 marksModerate
Explain Endothermic in about three points, with one example.
Answer
An endothermic reaction absorbs heat from the surroundings. Example: Photosynthesis
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q473 Mark3 marksModerate
Explain Precipitation in about three points, with one example.
Answer
A precipitate is an insoluble solid formed in a double-displacement reaction. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q483 Mark3 marksDifficult
Explain Chemical Reactions and Equations in about three points, with one example.
Answer
A chemical equation must be balanced for mass. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q494 Mark4 marksModerate
Write a long answer on Chemical Reactions and Equations. Include definition, explanation and one application.
Answer
Chemical Reactions and Equations — Combination, decomposition, displacement, double displacement. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q504 Mark4 marksModerate
Write a long answer on Redox. Include definition, explanation and one application.
Answer
Redox — Redox: oxidation is gain of oxygen or loss of electrons as taught. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q514 Mark4 marksModerate
Write a long answer on Chemical Reactions and Equations. Include definition, explanation and one application.
Answer
Chemical Reactions and Equations — Exothermic vs endothermic. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q524 Mark4 marksDifficult
Write a long answer on Chemical Reactions and Equations. Include definition, explanation and one application.
Answer
Chemical Reactions and Equations — Precipitation reactions. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q534 Mark4 marksModerate
Write a long answer on Balanced equation. Include definition, explanation and one application.
Answer
Balanced equation — A balanced chemical equation has the same number of atoms of each element on both sides. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q544 Mark4 marksModerate
Write a long answer on Combination reaction. Include definition, explanation and one application.
Answer
Combination reaction — In a combination reaction two or more substances join to form a single product. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q555 Mark5 marksModerate
Write a long answer on Decomposition. Include definition, explanation and one application.
Answer
Decomposition — A decomposition reaction splits one compound into two or more products, often with heat, light or electricity. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q565 Mark5 marksModerate
Write a long answer on Displacement. Include definition, explanation and one application.
Answer
Displacement — A more reactive metal can displace a less reactive metal from its salt solution. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q575 Mark5 marksDifficultRevision pick
Write a long answer on Redox. Include definition, explanation and one application.
Answer
Redox — Oxidation and reduction occur together in a redox reaction. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q585 Mark5 marksModerate
Write a long answer on Exothermic. Include definition, explanation and one application.
Answer
Exothermic — An exothermic reaction releases heat to the surroundings. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q595 Mark5 marksModerate
Write a long answer on Endothermic. Include definition, explanation and one application.
Answer
Endothermic — An endothermic reaction absorbs heat from the surroundings. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q605 Mark5 marksDifficult
Write a long answer on Precipitation. Include definition, explanation and one application.
Answer
Precipitation — A precipitate is an insoluble solid formed in a double-displacement reaction. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q61Assertion and Reason1 markModerate
Assertion (A): A chemical equation must be balanced for mass.
Reason (R): Chemical Reactions and Equations is a key idea in the chapter Chemical Reactions and Equations.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q62Assertion and Reason1 markModerate
Assertion (A): Combination, decomposition, displacement, double displacement.
Reason (R): Chemical Reactions and Equations is a key idea in the chapter Chemical Reactions and Equations.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q63Assertion and Reason1 markModerate
Assertion (A): Redox: oxidation is gain of oxygen or loss of electrons as taught.
Reason (R): Redox is a key idea in the chapter Chemical Reactions and Equations.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q64Assertion and Reason1 markDifficult
Assertion (A): Exothermic vs endothermic.
Reason (R): Chemical Reactions and Equations is a key idea in the chapter Chemical Reactions and Equations.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q65Assertion and Reason1 markModerate
Assertion (A): Precipitation reactions.
Reason (R): Chemical Reactions and Equations is a key idea in the chapter Chemical Reactions and Equations.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q66Assertion and Reason1 markModerate
Assertion (A): A balanced chemical equation has the same number of atoms of each element on both sides.
Reason (R): Balanced equation is a key idea in the chapter Chemical Reactions and Equations.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q67Assertion and Reason1 markModerate
Assertion (A): In a combination reaction two or more substances join to form a single product.
Reason (R): Combination reaction is a key idea in the chapter Chemical Reactions and Equations.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q68Assertion and Reason1 markDifficult
Assertion (A): A decomposition reaction splits one compound into two or more products, often with heat, light or electricity.
Reason (R): Decomposition is a key idea in the chapter Chemical Reactions and Equations.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q69Case Based4 marksModerateRevision pick
A student is revising Chemical Reactions and Equations and notes: “A more reactive metal can displace a less reactive metal from its salt solution.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Displacement.
(ii) A more reactive metal can displace a less reactive metal from its salt solution.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q70Case Based4 marksModerate
A student is revising Chemical Reactions and Equations and notes: “Oxidation and reduction occur together in a redox reaction.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Redox.
(ii) Oxidation and reduction occur together in a redox reaction.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q71Case Based4 marksModerate
A student is revising Chemical Reactions and Equations and notes: “An exothermic reaction releases heat to the surroundings.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Exothermic.
(ii) An exothermic reaction releases heat to the surroundings.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q72Case Based4 marksDifficult
A student is revising Chemical Reactions and Equations and notes: “An endothermic reaction absorbs heat from the surroundings.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Endothermic.
(ii) An endothermic reaction absorbs heat from the surroundings.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q73Case Based4 marksModerateRevision pick
A student is revising Chemical Reactions and Equations and notes: “A precipitate is an insoluble solid formed in a double-displacement reaction.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Precipitation.
(ii) A precipitate is an insoluble solid formed in a double-displacement reaction.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q74Case Based4 marksModerate
A student is revising Chemical Reactions and Equations and notes: “A chemical equation must be balanced for mass.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Chemical Reactions and Equations.
(ii) A chemical equation must be balanced for mass.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q75Case Based4 marksModerate
A student is revising Chemical Reactions and Equations and notes: “Combination, decomposition, displacement, double displacement.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Chemical Reactions and Equations.
(ii) Combination, decomposition, displacement, double displacement.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q76Case Based4 marksDifficult
A student is revising Chemical Reactions and Equations and notes: “Redox: oxidation is gain of oxygen or loss of electrons as taught.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Redox.
(ii) Redox: oxidation is gain of oxygen or loss of electrons as taught.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q77Competency Based3 marksModerateRevision pick
Competency practice: A classmate can recall the heading Chemical Reactions and Equations but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Exothermic vs endothermic. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q78Competency Based3 marksDifficult
Competency practice: A classmate can recall the heading Chemical Reactions and Equations but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Precipitation reactions. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q79Competency Based3 marksModerate
Competency practice: A classmate can recall the heading Balanced equation but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — A balanced chemical equation has the same number of atoms of each element on both sides. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q80Competency Based3 marksModerate
Competency practice: A classmate can recall the heading Combination reaction but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — In a combination reaction two or more substances join to form a single product. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q81Competency Based3 marksDifficultRevision pick
Competency practice: A classmate can recall the heading Decomposition but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — A decomposition reaction splits one compound into two or more products, often with heat, light or electricity. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q82Competency Based3 marksModerate
Competency practice: A classmate can recall the heading Displacement but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — A more reactive metal can displace a less reactive metal from its salt solution. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q83Competency Based3 marksModerate
Competency practice: A classmate can recall the heading Redox but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Oxidation and reduction occur together in a redox reaction. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q84Competency Based3 marksDifficult
Competency practice: A classmate can recall the heading Exothermic but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — An exothermic reaction releases heat to the surroundings. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q85Application Based3 marksModerate
Apply the idea of Endothermic to a real situation you might meet in school or daily life.
Answer
An endothermic reaction absorbs heat from the surroundings. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q86Application Based3 marksModerate
Apply the idea of Precipitation to a real situation you might meet in school or daily life.
Answer
A precipitate is an insoluble solid formed in a double-displacement reaction. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q87Application Based3 marksModerate
Apply the idea of Chemical Reactions and Equations to a real situation you might meet in school or daily life.
Answer
A chemical equation must be balanced for mass. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q88Application Based3 marksDifficult
Apply the idea of Chemical Reactions and Equations to a real situation you might meet in school or daily life.
Answer
Combination, decomposition, displacement, double displacement. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q89Application Based3 marksModerate
Apply the idea of Redox to a real situation you might meet in school or daily life.
Answer
Redox: oxidation is gain of oxygen or loss of electrons as taught. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q90Application Based3 marksModerate
Apply the idea of Chemical Reactions and Equations to a real situation you might meet in school or daily life.
Answer
Exothermic vs endothermic. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q91HOTS3 marksModerate
HOTS: If someone ignored the idea “Precipitation reactions”, what mistake could they make while solving a question from Chemical Reactions and Equations?
Answer
They would use the wrong term or the reverse relation. Remember: Precipitation reactions. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q92HOTS3 marksModerate
HOTS: If someone ignored the idea “A balanced chemical equation has the same number of atoms of each element on both sides”, what mistake could they make while solving a question from Chemical Reactions and Equations?
Answer
They would use the wrong term or the reverse relation. Remember: A balanced chemical equation has the same number of atoms of each element on both sides. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q93HOTS3 marksDifficultRevision pick
HOTS: If someone ignored the idea “In a combination reaction two or more substances join to form a single product”, what mistake could they make while solving a question from Chemical Reactions and Equations?
Answer
They would use the wrong term or the reverse relation. Remember: In a combination reaction two or more substances join to form a single product. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q94HOTS3 marksModerate
HOTS: If someone ignored the idea “A decomposition reaction splits one compound into two or more products, often with heat, light or electricity”, what mistake could they make while solving a question from Chemical Reactions and Equations?
Answer
They would use the wrong term or the reverse relation. Remember: A decomposition reaction splits one compound into two or more products, often with heat, light or electricity. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q95HOTS3 marksModerate
HOTS: If someone ignored the idea “A more reactive metal can displace a less reactive metal from its salt solution”, what mistake could they make while solving a question from Chemical Reactions and Equations?
Answer
They would use the wrong term or the reverse relation. Remember: A more reactive metal can displace a less reactive metal from its salt solution. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q96HOTS3 marksDifficult
HOTS: If someone ignored the idea “Oxidation and reduction occur together in a redox reaction”, what mistake could they make while solving a question from Chemical Reactions and Equations?
Answer
They would use the wrong term or the reverse relation. Remember: Oxidation and reduction occur together in a redox reaction. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q97NCERT-style2 marksModerate
NCERT-style exercise: In your own words, write what the chapter teaches about Exothermic.
Answer
An exothermic reaction releases heat to the surroundings. Keep the answer as short as the in-text questions in the textbook.
Explanation
This is original practice in the style of NCERT in-text/exercise questions. It is not copied from any solutions website.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q98NCERT-style2 marksModerate
NCERT-style exercise: In your own words, write what the chapter teaches about Endothermic.
Answer
An endothermic reaction absorbs heat from the surroundings. Keep the answer as short as the in-text questions in the textbook.
Explanation
This is original practice in the style of NCERT in-text/exercise questions. It is not copied from any solutions website.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q99NCERT-style2 marksModerate
NCERT-style exercise: In your own words, write what the chapter teaches about Precipitation.
Answer
A precipitate is an insoluble solid formed in a double-displacement reaction. Keep the answer as short as the in-text questions in the textbook.
Explanation
This is original practice in the style of NCERT in-text/exercise questions. It is not copied from any solutions website.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q100NCERT-style2 marksDifficult
NCERT-style exercise: In your own words, write what the chapter teaches about Chemical Reactions and Equations.
Answer
A chemical equation must be balanced for mass. Keep the answer as short as the in-text questions in the textbook.
Explanation
This is original practice in the style of NCERT in-text/exercise questions. It is not copied from any solutions website.
Meta
Class: Class 10 · Subject: Science · Chapter: Chemical Reactions and Equations · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
FAQs
Are these official CBSE board questions?
No. They are original practice questions aligned to NCERT topics used in CBSE classrooms. Official sample papers are published on cbseacademic.nic.in.
Will these questions appear in the board exam?
Nobody can promise a question. Use them for revision of frequently tested concepts and exam-style practice.
Is the chapter list the latest NCERT list?
Yes, the catalog follows current NCERT textbooks used in CBSE schools (including new middle-stage books such as Ganita Prakash and Curiosity). Always match the book issued by your school.
How should I use the 100 questions?
Try the question first, then tap Show answer. Mix MCQs with long answers. Revise formulas and diagrams from the textbook alongside this set.
Where are NCERT solutions?
Open the NCERT-style practice link on this subject or chapter. For word-for-word textbook exercise answers, use the NCERT book itself; we do not copy solution keys from other websites.
What is the suggested URL pattern?
Hub /cbse/, then /cbse/class-10/, then subject and chapter slugs.
Why is this a separate URL?
So students searching for “Important Formulas” land on a filtered set, while the chapter page remains the full 100-question bank. Same facts, different search intent.
Today's 3-step path
Follow this loop every day: mixed test, current affairs, then today's subject. A new set arrives tomorrow.
