CBSE Class 12 Chemistry Chemical Kinetics Assignment Set A

Question. The rate constant of first order reaction is 3 × 10^–6 per second. The initial concentration is 0.10 M.
The initial rate is:
(a) 3 × 10^–7 mol/litre/sec
(b) 3 × 10^–8 mol/litre/sec
(c) 3 × 10^–5 mol/litre/sec
(d) 3 × 10^–8 mol/litre/sec

Question. The half-life of a substance in a certain enzymecatalysed reaction is 138 s. The time required for the concentration of the substance to fall from 1.28 mg L^–1 to 0.04 mg L^–1 is
(a) 414 s
(b) 552 s
(c) 690 s
(d) 276 s 

Question. Half-life period of a first order reaction is 1386 seconds. The specific rate constant of the reaction is
(a) 0.5 × 10–2 s^–1
(b) 0.5 × 10–3 s^–1
(c) 5.0 × 10–2 s^–1
(d) 5.0 × 10–3 s^–1 

Question. The activation energy for a simple chemical reaction A ⇌ B is Ea in forward direction. The activation energy for reverse reaction
(a) is negative of Ea
(b) is always less than Ea
(c) can be less than or more than Ea
(d) is always double of Ea. 

Question. When a biochemical reaction is carried out in laboratory, outside the human body in absence of enzyme, then rate of reaction obtained is 10^–6 times, the activation energy of reaction in the presence of enzyme is
(a) 6/RT
(b) P is required
(c) different from Ea obtained in laboratory
(d) can’t say anything. 

Question. Which of the following statement is true for the reaction, H₂ + Br₂ →2HBr . The rate law is [ H₂ ][ Br₂ ]1/ 2 dx/dt=k  
(a) order of reaction is 1.5
(b) molecularity of the reaction is 2
(c) by increasing the concentration of Br₂ four times the rate of reaction is doubled
(d) all the above are correct.

Question. In a reaction, A + B → product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentration of both the reactants (A and B) are doubled, rate law for the reaction can be written as
(a) rate = k[A][B]²
(b) rate = k[A]²[B]²
(c) rate = k[A][B]
(d) rate = k[A]²[B]

Question. For the reaction : H₂ Cl₂ →^sunlight 2HCl the order of reaction is 
(a) 0
(b) 2
(c) 1
(d) 3

Question. The rate of a first order reaction is 1.5 × 10^–2 mol L^–1 min^–1 at 0.5 M concentration of the reactant. The half-life of the reaction is
(a) 0.383 min
(b) 23.1 min
(c) 8.73 min
(d) 7.53 min

Question. Activation energy of a chemical reaction can be determined by
(a) evaluating rate constants at two different temperatures
(b) evaluating velocities of reaction at two different temperatures
(c) evaluating rate constant at standard temperature
(d) changing concentration of reactants.