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

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

1. First

2. Second

3. Third

4. 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:

1. r = K[O₃]²

2. r = K[O₃]²[O₂]^-1

3. r = K[O₃][O₂]

4. 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?

1. 16

2. 32

3. 64

4. 128

The rate constant (K) for the reaction 2A +B $\to$ Product was found to be 2.5x10^-5 litre mol^-1 sec^-1 after 15 sec, 2.60 x10^-5 litre mol^-1sec^-1 after 30 sec and 2.55 x10^-5litre mol^-1 sec^-1 after 50 sec. The order of reaction is:

1. 2

2. 3

3. zero

4. 1

A reaction A₂ + B₂ $\to$ 2AB occurs by the following mechanism:

A₂ $\to$ A + A               .....(slow)

A + B₂ $\to$ AB + B       .....(fast)

A + B $\to$ AB               .....(fast)

Its order would be:

1. 3/2

2. 1

3. 0

4. 2

For a given reaction, the presence of a catalyst reduces the energy of activation by 2 kcal at 27 ^oC. The rate of reaction will be increased by:

1. 20 times

2. 14 times

3. 28 times

4. 2 times

What fraction of a reactant showing first order remains after 40 minute if t_1/2 is 20 minute?

1. 1/4

2. 1/2

3. 1/8

4. 1/6

Rate equation for a second order reaction is:

1. K = (2.303/t) log {a/(a-x)}

2. K = (1/t) log {a/(a-x)}

3. K = $(\frac{1}{{\left(a\right)}_t}-\frac{1}{{\left(a_o\right)}_t})* \frac{1}{t}$

4. K = (1/t²) log {a/(a-x)}

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:

1. r = K[NO₂]²[F₂]

2. r = K[NO₂ ][F₂]

3. r = K[NO₂]

4. r = K[F₂]