Which of the following represents the factor by which the rate of a zero-order reaction increases when the temperature is raised from 10°C to 100°C, if the rate doubles for every 10°C rise in temperature?

1. 256 times

2. 512 times

3. 64 times

4. 128 times

The half-life of a certain enzyme catalysed reaction is 138 s, that follow the 1st order kinetics. The time required for the concentration of the substance to fall from 1.28 mg L^–1 to 0.04 mg L^–1, is:

1. 276 s 

2. 414 s

3. 552 s 

4. 690 s

The reaction of hydrogen and iodine monochloride is given as: 
H₂(g) + 2ICl(g) → 2HCl(g) + I₂(g) 
This reaction is of first order with respect to H₂(g) and ICl(g), for which of the following proposed mechanisms:
Mechanism A: 
H₂(g) + 2ICl(g) → 2HCl(g) + I₂(g) 
Mechanism B: 
H₂(g) + ICl(g) →HCl(g) + HI(g); slow 
HI(g) + ICl(g) →HCl(g) + I₂(g); fast

1. B Only

2. A and B both

3. Neither A nor B

4. A only

In a first order reaction A \(\overset{                         }{\rightarrow}\) B, if k is rate constant and initial concentration of the reactant A is 0.5 M then the half-life is :

(1) \(\frac{0 . 693}{0 . 5 k}\)

(2) \(\frac{log   2}{k}\)

(3) \(\frac{log   2}{k \sqrt{0 . 5}}\)

(4) \(\frac{ln   2}{k}\)

If 60% of a first-order reaction was completed in 60 min, 50% of the same reaction would be completed in approximately: 
(log 4 = 0.60, log 5 = 0.69)