A zero order reaction is one:

(1) In which reactants do not react

(2) In which one of the reactants is in large excess

(3) Whose rate does not change with time

(4) Whose rate increases with time

For A+B $\to$C+D, $∆$H = -20 kJmol^-1 the activation energy of the forward reaction is 85 kJ mol^-1. The activation energy for backward reaction is...... kJ mol^-1

1. 105

2. 85

3. 40

4. 65

For the elementary reaction M $\to$ N, the rate of disappearance of M increases by a factor of 8 upon doubling the concentration of M. The order of the reaction with respect to M is:

(1) 4

(2) 3

(3) 2

(4) 1

The rate constant for a second order reaction is 8x10^-5 M^-1 min^-1 . How long will it take a 1M solution to be reduced to 0.5M?

(1) 8.665 x 10³ minute

(2) 8 x 10^-5 minute

(3) 1.25 x 10⁴ minute

(4) 4x10^-5 minute

The time for the half-life of a first-order reaction is 1 hr. The time taken for 87.5% completion of the reaction is-

1. 1 hour

2. 2 hour

3. 3 hour

4. 4 hour

Which order of reaction obeys the relation t_1/2 = 1/Ka?

(a) First

(b) Second

(c) Third

(d) Zero

The chemical reaction, 2O₃ $\to$3O₂ proceeds as follows;

O₃ $\rightleftharpoons$O₂ + O .....(Fast)

O+O₃ $\to$ 2O₂ ....(Slow)

The rate law expression should be:

(a) r = K[O₃]²

(b) r = K[O₃]²[O₂]^-1

(c) r = K[O₃][O₂]

(d) unpredictable

The rate of reaction becomes 2 times for every 10°C rise in temperature. How the rate of reaction will increase when temperature is increased from 30°C to 80°C?

(a) 16

(b) 32

(c) 64

(d) 128

The fraction of a reactant showing first-order reaction remains after 40 minutes if t_1/2 is 20 minutes -

1. 1/4

2. 1/2

c. 1/8

4. 1/6

For the reaction 2NO₂ + F₂ → 2NO₂F, following

mechanism has been provided,

 NO₂ + F₂   $\stackrel{slow}{\to }$  NO₂F+F

NO₂ + F   $\stackrel{fast}{\to }$ NO₂F

Thus, rate expression of the above

reaction can be written as:

(a) r = K[NO₂]²[F₂]

(b) r = K[NO₂ ][F₂]

(c) r = K[NO₂]

(d) r = K[F₂]