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⚗️ CBSE Class 12 Chemistry Important Questions 🧪
Board Exam 2026 - High Priority MCQs with Detailed Answers
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CBSE Class 12 Chemistry Important Questions Questions & Answers
Welcome to GKSchools, your trusted educational portal for competitive exam preparation. This page is dedicated to CBSE Class 12 Chemistry Important Questions, a crucial segment under the CBSE Study Notes syllabus. Understanding CBSE Class 12 Chemistry Important Questions is essential for students and aspirants aiming to secure high ranks in competitive examinations. In this detailed study guide, we break down the core principles, solve practice questions, and share expert preparation strategies to help you gain mastery over this topic. Why is this topic important? Questions on CBSE Class 12 Chemistry Important Questions are frequently asked in major exams like SSC CGL, UP Police Constable, Railway (RRB) NTPC, Bank PO, and State PSC Exams. Examiners test your logical understanding, speed, and accuracy in this segment. Scoring well here requires a combination of conceptual clarity and regular mock test practice. On this page, you will find curated study materials, solved examples, and interactive quizzes designed by our editorial board to meet the latest 2026 exam standards. To get the maximum benefit from this guide, we recommend starting with the fundamental concepts, followed by attempting the quiz questions at the bottom of the page. Do not forget to bookmark this resource and check back regularly as we update our daily current affairs and subject notes to reflect the latest notification and syllabus updates. Start your learning journey today and elevate your exam preparation to the next level!
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⏱️ Questions
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⭐ HIGH PRIORITY
1
The unit of rate constant for a zero order reaction is:
✅ Correct Answer: (a) mol L⁻¹ s⁻¹
For zero order reaction: Rate = k[A]⁰ = k
Explanation: Units of k = Units of rate = mol L⁻¹ s⁻¹
Remember: Zero order → mol L⁻¹ s⁻¹, First order → s⁻¹, Second order → L mol⁻¹ s⁻¹
Remember: Zero order → mol L⁻¹ s⁻¹, First order → s⁻¹, Second order → L mol⁻¹ s⁻¹
⭐ HIGH PRIORITY
2
Which of the following is a primary halide?
✅ Correct Answer: (c) n-propyl chloride
CH₃-CH₂-CH₂-Cl (1° halide)
Explanation: In primary halide, the carbon bearing halogen is attached to only one carbon atom. n-propyl chloride has the -Cl on a primary carbon.
⭐ HIGH PRIORITY
3
The coordination number of Ni in [Ni(NH₃)₆]²⁺ is:
✅ Correct Answer: (c) 6
Six NH₃ ligands are attached to central Ni²⁺ ion
Explanation: Coordination number = Number of ligands directly attached to the central metal ion. Here, 6 ammonia molecules are coordinated with Ni²⁺.
⭐ HIGH PRIORITY
4
Aldehydes can be distinguished from ketones using:
✅ Correct Answer: (d) All of the above
Aldehydes give positive test, ketones don't
Explanation: All three tests distinguish aldehydes from ketones. Aldehydes reduce Fehling's, Benedict's, and Tollen's reagent due to presence of -CHO group. Ketones don't react.
⭐ HIGH PRIORITY
5
Faraday's constant (F) is equal to:
✅ Correct Answer: (a) 96500 C mol⁻¹
F = e × Nₐ = 1.6 × 10⁻¹⁹ × 6.022 × 10²³ ≈ 96500 C mol⁻¹
Explanation: Faraday constant is the charge carried by one mole of electrons. It's fundamental in electrochemistry calculations.
⭐ HIGH PRIORITY
6
The half-life of a first order reaction is 30 minutes. What is the rate constant?
✅ Correct Answer: (a) 0.0231 min⁻¹
k = 0.693/t₁/₂ = 0.693/30 = 0.0231 min⁻¹
Explanation: For first order reactions: k = 0.693/t₁/₂. This is one of the most important formulas for board exams!
⭐ HIGH PRIORITY
7
Which of the following has the highest conductivity in aqueous solution?
✅ Correct Answer: (c) 0.1 M NaCl
NaCl is a strong electrolyte - completely ionizes
Explanation: NaCl (strong electrolyte) > CH₃COOH, NH₄OH (weak electrolytes) > C₆H₁₂O₆ (non-electrolyte). Higher ionization = higher conductivity.
⭐ HIGH PRIORITY
8
Identify the chiral molecule:
✅ Correct Answer: (a) 2-Bromobutane
Contains an asymmetric carbon (chiral center)
Explanation: In 2-bromobutane, C-2 is attached to 4 different groups (H, Br, CH₃, C₂H₅), making it chiral. Chiral molecules show optical isomerism.
⭐ HIGH PRIORITY
9
The IUPAC name of CH₃-CO-CH₃ is: