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.

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 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]

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

1. 1 hour

2. 2 hour

3. 3 hour

4. 4 hour