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 kJ mol^-1 , the activation energy of the forward reaction is 85 kJ mol^-1. The activation energy for the backward reaction is…. kJ mol^-1.

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 will be:

1. 4

2. 3

3. 2

4. 1

The rate constant value for a zero-order reaction is 2 x10^-2 mol L^-1 sec^-1. If the concentration of the reactant after 25 sec is 0.5 M, then the initial concentration of reactant is: 

1. 0.5 M

2. 1.25 M

3. 12.5M

4. 1.0 M

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 activation energy for a reaction is 9.0 kcal/mol. The increase in the rate constant when its temperature is increased from 298K to 308K is:

1. 10%

2. 100%

3. 50%

4. 63%

For a certain reaction of order \('n'\) the time for half change \(t_{1/2}\) is given by; \(=,t_{1/2}=\dfrac{2-\sqrt2}{K}\times C^{1/2}_0,\) where \(K\) is rate constant and \(C_0\) is initial concentration. The value of \(n\) is:

1. 1

2. 2

3. 0

4. 0.5

In the following first order competing reactions:

A + Reagent $\to$ Product

B + Reagent $\to$ Product

The ratio of K₁/K₂ if only 50% of B will have been reacted when 94% of A has been reacted in same time is:

1. 4.06

2. 0.246

3. 2.06

4. 0.06

For a reversible reaction A $\underset{k_2}{\overset{k_1}{\rightleftharpoons }}$ B, Ist order in both the directions, the rate of reaction is given by:

1. K₁[A]

2. -K₂B

3. K₁[A] + K₂[B]

4. K₁[A] - K₂[B]