CBSE Class 12 Chemistry Chemical Kinetics Worksheet Set B

Question. When a chemical reaction takes place, during the course of the reaction the rate of reaction:(excluding zero order)
a. Keeps on increasing with time
b. Remains constant with time
c. Keeps on decreasing with time
d. Shows irregular trend with time

Answer: C

 

Question. When a catalyst is used in an equilibrium process:
a. It increases the rate of forward reaction
b. It decreases the rate of backward reaction
c. It decreases activation energy of forward process and decreases activation energy of backward process
d. It fastens the attainment of equilibrium by lowering activation energy

Answer: D

Question. 75% of a first order reaction is completed in 30 minutes, what is the time required for 93.75% of the reaction in minutes?
a. 45
b. 120
c. 90
d. 60

Answer: D

Question. The half-life period for a first order reaction is:
a. Independent of concentration
b. Proportional to concentration
c. Inversely proportional to concentration
d. Inversely proportional to the square of the concentration

Answer: A

Question. On increasing the pressure three fold, the rate of reaction of 2H2S + O2 → products, would increase
a. 3 times
b. 9 times
c.12 times
d. 27 times

Answer: D

Question. The value of rate constant for a first order is 2.303 × 10-2 sec–1 What will be the time required to reduce the concentration to (1/10)th of the initial concentration?
a. 100 sec
b. 10 sec
c. 2303 sec
d. 23.03 sec

Answer: A

Question. The number of molecules of the reactants taking part in a single step of the reaction is indicative of:
a. Order of a reaction
b. Molecularity of a reaction
c. Fast step of the mechanism of a reaction
d. Half-life of the reaction

Answer: B

Question. Half-life period of a first order reaction is 10min. What percentage of the reaction will be completed in 100 min?
a. 25%
b. 50%
c. 99.9%
d. 75%

Answer: C

Question. Consider the reaction, 2N₂O₅ → 4NO₂ + O₂ In the reaction NO₂ is being formed at the rate of 0.0125 mol L^–1 S^–1. What is the rate of reaction at this time?
a. 0.0018 mol^–1 L S^–1
b. 0.0031 mol^–1 ltr–1 sec^–1
c. 0.0041 mol^–1 L S^–1
d. 0.050 mol L^–1 S^–1

Answer: B

Question. The rate constant for a first order reaction at 300°C for which Ea is 35 Kcal mol^–1 and frequency constant 'A' is 1.45 × 10¹¹ sec^–1 is:
a. 10 × 10^–2 S^–1
b. 5.37 × 10¹⁰ S^–1
c. 5 × 10^–4 S–1
d. 7.94 × 10^–3 S^–1

Answer: D

Question. The expression to calculate time required for completion of zero order reaction is:
a. t = [R_o]/k
b. t = [R] −[R_o]
c. t = k/[R_o]
d. t = [R_o] - [R] / [R_o]

Answer: A

Question. Which of the following does not effect half-life of first order reaction?
a. Initial concentration
b. Catalyst
c. Temperature
d. Pressure

Answer: A

Question. Units of specific reaction rate for second order reaction:
a. S^–1
b. mol L^–1 S^–1
c. L mol^–2 S^–1
d. L mol^–1 S^–1

Answer: D

Question. For which order half-life period is independent of initial concentration?
a. Zero
b. First
c. Second
d. Third

Answer: B

Question. The order of reaction is decided by:
a. Temperature
b. Molecularity
c. Pressure
d. Mechanism of reaction as well as relative concentration of reactants

Answer: D

Question. If 60% of first order reaction was completed in 60min, 50% of the same reaction would be completed in approximately:
a. 45 min
b. 60 min
c. 40 min
d. 50 min

Answer: A

Question. In a reaction 2X → Y, the concentration of X decreases from 3.0 moles/litre to 2.0 moles/litre in 5 minutes. The rate of reaction is:
a. 0.1 mol L^–1 min^–1
b. 5 mol L^–1 min^–1
c. 1 mol L^–1 min^–1
d. 0.5 mol L^–1 min^–1

Answer: A

Question. The unit of rate and rate constant are same for a:
a. Zero order reaction
b. First order reaction
c. Second order reaction
d. Third order reaction

Answer: A

Question. Rate constant of a reaction (K) is 300 L² mol^–2 s^–1 what is the order of reaction?
a. First
b. Second
c. Third
d. Zero

Answer: C
 

Question. Which one of the following statements for the order of a reaction is incorrect?
a. Order of reaction is always whole number
b. Order can be determined only experimentally
c. Order is not Influenced by stoichiometric coefficient of the reactants
d. Order of reaction is sum of power to the concentration terms of reactant to express the rate of reaction while writing the rate law.

Answer: A

Question. t_1/2 for a first order reaction is 10 min. Starting with 10 M, the rate after 20 min is:
a. 0.0693 M min^–1
b. 0.0693 × 5 M min^–1
c. 0.0693 × 2.5 M min^–1
d. 0.0693 × 10 M min^–1

Answer: C

Question. For a first order reaction the rate constant is 6.909 min^–1. The time taken for 75% conversion in minutes is:
a. (3/2) log 2
b. (2/3) log 3
c. (2/3) log 2
d. (3/2) log 3/4

Answer: C

Question. For the first order reaction half-life is 14 sec, the time required for the initial concentration to reduce to 1/8 of its value is:
a. (14)³ sec
b. 28 sec
c. 42 sec
d. (14) 2sec

Answer: C

Question. Under what conditions a biomolecular reaction may be kinetically of first order?
a. When both reactants have same concentration.
b. When one of the reacting species is in large excess
c. When the reaction is at equilibrium
d. When the activation energy of reaction is less

Answer: B

Question. The order of a reaction for an esterification process is :
a. Zero
b. First
c. Second
d. Pseudo first order

Answer: C

Question. Consider the following statements.
The rate law for the acid catalysed hydrolysis of an ester being given israte = k[H⁺][ester] = k' [ester], if the acid concentration is doubled at constant ester concentration.
I. The second order rate constant, k is doubled
II. The pseudo first order rate constant, k' is doubled
III. The rate of the reaction is doubled
Which of the above statement are correct?
a. I and II
b. II and III
c. I and III
d. I, II and III

Answer: B

Question. The activation energy in a chemical reaction is defined as:
a. The difference in energy of reactants and products
b. The sum of energies of reactant and products
c. The difference in energy of intermediate complex with the average energy of reactants and products
d. The difference in energy of intermediate complex and the average energy of reactants

Answer: D

Question. A → B is a first order reaction. The initial concentration of A is 0.2 mol L^–1. After 10 min, the concentration of B is found to be 0.18 mol L^–1. The rate constant (in min^–1) for the reaction is:
a. 0.2303
b. 2.303
c. 0.693
d. 0.01

Answer: A

Question. A first order reaction is 20% complete in 10 minutes. What is the specific rate constant for the reaction?
a. 0.0970 min^–1
b. 0.009 min^–1
c. 0.0223 min^–1
d. 2.223 min^–1

Answer: C

Question. Which of the following statement is not correct?
a. In zero order reaction, the rate of the reaction remains constant through out
b. A second order reaction would becomes a pseudo first order reaction, when one of the reactants is taken in large excess
c. The units of first order rate constant depends on the units of the concentration terms used
d. In the first order reaction, the plot of log (a-x ) vs time follows straight line equation

Answer: C

Question. The rate law for the reaction, xA + yB → mP + nQ is rate
= k [A]^c [B]^d what is the total order of the reaction?
a. x + y
b. m + n
c. c + d
d. Two

Answer: C

Question. The rate equation for a reaction, A → B is r = K[A]⁰ if the initial concentration of the reactant is a mol dm^–3, the half period of the reaction is:
a. k/a
b. a/k
c. 2a/k
d. a/2k

Answer: D

Question. For a first order reaction, the time taken to reduce the initial concentration by a factor of 1/4 is 20 min. the time required to reduce initial concentration by a factor of 1/16 is:
a. 20 min
b. 10 min
c. 80 min
d. 5 min

Answer: D

Question. In a first order reaction the concentration of reactants decreases from 400mol L^–1 to 25 mol L^–1 in 200 seconds. The rate constant for the reaction is:
a. 1.01386 S^–1
b. 2 × 10 S^–1
c. 1.386 × 10^–2 S^–1
d. 3.4 × 10 S^–1

Answer: C

Question. Which one of the following is wrongly matched?
a. Saponification of CH₃COOC₂H₅ – second order reaction
b. Hydrolysis of CH₃COOCH₃ – Pseudo unimolecular reaction
c. Decomposition of H₂O₂ – first order reaction
d. Combination of H₂ and Br₂ to give HBr – zero order reaction

Answer: D

Question. The temperature dependence of the rate of a chemical reaction can be explained by Arrhenius equation which is:
a. K = Ae^–Ea/RT
b. K = Ae^Ea/RT
c. K = Ae x E_a x RT
d. K = Ae x RT / E_a

Answer: A

Question. Which of the following statements about the catalyst is true?
a. A catalyst makes the reaction feasible by making ΔG more negative
b. A catalyst makes equilibrium constant more favorable for forward reaction
c. A catalyst accelerate rate of reaction by bringing down the activation energy
d. A catalyst always increases the rate of reaction

Answer: C

Question. In a zero order reaction for every 10°C rise of temperature, the rate is doubled. If the temperature is increased from 10°C to 100°C, rate of reaction will becomes:
a. 256 times
b. 512 times
c. 64 times
d. 128 times

Answer: B

Question. The rate constant K₁ and K₂ for two different reactions are 10¹⁶.e^–2000/T and 10¹⁵. e^–1000/T, respectively. The temperature at which K₁ = K₂ is:
a. 1000K
b. (2000/2.303) K
c. 2000K
d. (1000/2.303) K

Answer: D

 

Please click on below link to download CBSE Class 12 Chemistry Chemical Kinetics Worksheet Set B