Assertion-Reason questions are an important section of the Class 12th Chemistry examination and NEET, IIT-JEE, designed to assess students' analytical thinking, conceptual clarity, and ability to establish logical relationships between scientific statements. These questions typically present two interconnected statements—an Assertion (A) and a Reason (R)—and require candidates to evaluate their individual validity as well as the causal link between them. Mastering this format not only strengthens problem-solving skills but also aligns with the evolving pattern of board exams, where such questions carry significant weight in Section A (MCQ-based). This comprehensive collection of Assertion-Reason questions serves as an essential practice resource to build precision, speed, and confidence for the final examination.
Assertion Reason Questions for Class 12th Download PDF
Class 12 Chemistry
Assertion-Reason Questions (One from Each Chapter)
Options:
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Chapter 1: Solutions
Assertion (A): The boiling point of a solution is higher than that of the pure solvent.
Reason (R): Addition of a non-volatile solute increases the vapour pressure of the solution.
(c) A is true, but R is false.
Chapter 2: Electrochemistry
Assertion (A): The standard reduction potential of copper is positive (+0.34 V).
Reason (R): Copper has a high tendency to get reduced compared to hydrogen.
(a) Both A and R are true, and R is the correct explanation of A.
Chapter 3: Chemical Kinetics
Assertion (A): For a zero-order reaction, the rate is independent of the concentration of reactants.
Reason (R): The rate law for zero-order reaction is rate = k [A]^0.
(a) Both A and R are true, and R is the correct explanation of A.
Chapter 4: d- and f-Block Elements
Assertion (A): Transition metals show variable oxidation states.
Reason (R): The energy difference between (n-1)d and ns orbitals is small.
(a) Both A and R are true, and R is the correct explanation of A.
Chapter 5: Coordination Compounds
Assertion (A): [Co(NH₃)₆]³⁺ is an inner orbital complex.
Reason (R): It is a low-spin complex with d²sp³ hybridization.
(a) Both A and R are true, and R is the correct explanation of A.
Chapter 6: Haloalkanes and Haloarenes
Assertion (A): Chlorobenzene is less reactive than benzyl chloride towards nucleophilic substitution.
Reason (R): In chlorobenzene, the C–Cl bond has partial double bond character due to resonance.
(a) Both A and R are true, and R is the correct explanation of A.
Chapter 7: Alcohols, Phenols and Ethers
Assertion (A): Phenol is more acidic than ethanol.
Reason (R): Phenoxide ion is stabilized by resonance, whereas ethoxide ion is not.
(a) Both A and R are true, and R is the correct explanation of A.
Chapter 8: Aldehydes, Ketones and Carboxylic Acids
Assertion (A): Carboxylic acids have higher boiling points than aldehydes and ketones of comparable molecular mass.
Reason (R): Carboxylic acids form intermolecular hydrogen bonds leading to dimerization.
(a) Both A and R are true, and R is the correct explanation of A.
Chapter 9: Amines
Assertion (A): Aniline is a weaker base than ethylamine.
Reason (R): The lone pair on nitrogen in aniline is delocalized into the benzene ring due to resonance.
(a) Both A and R are true, and R is the correct explanation of A.
Chapter 10: Biomolecules
Assertion (A): α-D-Glucose and β-D-Glucose are anomers.
Reason (R): They differ in configuration only at the C-1 carbon atom.
(a) Both A and R are true, and R is the correct explanation of A.
