NCERT Class 12 Chemistry General Awareness Questions with Answers
NCERT Class 12 Chemistry
QUESTIONS
NCERT Class 12 Chemistry General Awareness Questions with Answers
61 Which of the following statements about the catalyst is true?
A A catalyst accelerates the rate of reaction by bringing down the activation energy.
B A catalyst does not participate in reaction mechanism.
C A catalyst makes the reaction feasible by making ∆G more negative.
D A catalyst makes equilibrium constant more favourable for forward reaction.
Answer: A catalyst accelerates the rate of reaction by bringing down the activation energy.
62 Which among the following is a false statement?
A For a first order reaction,
B Molecularity of a reaction may be zero or fraction.
C Rate of zero order reaction is independent of initial concentration of reactant.
D Half life of a third order reaction is inversely proportional to square of initial concentration of the reactant.
Answer: Molecularity of a reaction may be zero or fraction.
63 A solution containing 10 g per dm3 of urea (molar mass 60 g mol-1) is isotonic with 5% solution of non-volatile solute, MB of solute is
A 250 g mol-1
B 300 g mol-1
C 350 g mol-1
D 200 g mol-1
64 The value of Henry’s constant KH is _________ .
A greater for gases with higher solubility.
B greater for gases with lower solubility.
C constant for all gases.
D not related to the solubility of gases.
Answer: greater for gases with lower solubility.
65 Which of the following reactions is an example of auto reduction?
A Fe3O4 + 4CO → 3Fe + 4CO2
B Cu2O + C → 2Cu + CO
C Cu2+ (aq) + Fe (s) → Cu (s) + Fe2+ (aq)
D Cu20 + 1/2 Cu2S → 3Cu + 1/2 SO2
Answer: Cu20 + 1/2 Cu2S → 3Cu + 1/2 SO2
66 The electrolytic reduction technique is used in the extraction of
A Highly electropostive elements.
B Transition metals.
C Highly electronegative elements.
D Metalloids.
Answer: Highly electropostive elements.
67 If molality of dilute solution is doubled, the value of molal depression constant (Kf) will be
A halved
B tripled
C unchanged
D doubled
68 Which one of the following metals is required as cofactor by all enzymes utilizing ATP in phosphate transfer?
69 An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because _________ .
A it gains water due to osmosis.
B it loses water due to reverse osmosis.
C it gains water due to reverse osmosis.
D it loses water due to osmosis.
Answer: it loses water due to reverse osmosis.
70 What will be the fraction of molecules having energy equal to or greater than activation energy, Ea?
A e-Ea/Rt
B Ae-Ea/Rt
C A
D K