3A $\to$ C + D, For this reaction it is observed that when initial concentration of A is 10 mole/lit then t_1/2 value of this reaction is 40 min and when initial concentration of A is 20 mole / lit, t_1/2 value has been changed into 20 min. Which of the following is true?

(1) The reaction is bimolecular reaction

(2) This reaction is an example of radioactive disintegration

(3) The reaction is of 1st order

(4) The order of the reaction is two

In the following reaction: xA →  yB

$\log \left(-\frac{d\left[A\right]}{d\mathrm{t }}\right)=$ $\log$ $\left(\frac{d\left[B\right]}{dt}\right)$ $+$ $0.3$ 

where the -ve sign indicates the rate of disappearance of the reactant. Then, x : y equals:

Half-life is independent of the concentration of a reactant. After 10 minutes, the volume of N₂ gas is 10 L and after complete reaction, it is 50 L. Hence, the rate constant is:

1. $\frac{2.303}{10}$log 5 min^-1

2. $\frac{2.303}{10}$ log 1.25 min^-1

3. $\frac{2.303}{10}$ log 2 min^-1

4. $\frac{2.303}{10}$ log 4 min^-1

The activation energies of the forward and backward reactions in the case of a chemical reaction are 30.5 and 45.4 KJ/mol respectively. The reaction is

1. Exothermic

2. Endothermic

3. Neither exothermic nor endothermic

4. Independent of temperature

The t_0.5 for the first order reaction.

PCl₅(g) $\to$PCl₃(g) + Cl₂(g) is 20 min. The time in which the conc. of PCl₅ reduces to 25% of the initial conc. is close to 

1. 22 min

2. 40 min

3. 90 min

4. 50 min

Consider a reaction A + B → C. If the initial concentration of A was reduced from 4M to 2M in 1 hour and from 2M to 1M in 0.5 hours, the order of the reaction is

1. One

2. Zero

3. Two

4. Three

A gaseous reaction A₂(g) → B(g) + $\frac{1}{2}C$(g) shows increase in pressure from 100 mm to 120 mm in 5 minutes. The rate of disappearance of A₂ will be : 

During the formation of ammonia by Haber's process N₂ + 3H₂ → 2NH₃, the rate of appearance of NH₃ was measured as 2.5 x 10^-4 mol L^-1 s^-1. The rate of disappearance of H₂ will be: 

1. 2.5 x 10^-4 mol L^-1 s^-1

2. 1.25 x 10^-4 mol L^-1 s^-1

3. 3.75 x 10^-4 mol L^-1 s^-1

4. 15.00 x 10^-4 mol L^-1 s^-1

For a chemical reaction, A $\to$  products, the rate of reaction doubles when the concentration of A is increased by 4 times. The order of the reaction is 

1. 4

2. 0

3. 1/2

4. 1

The correct expression for the 3/4th life of a first-order reaction is:

$1. \frac{\mathrm{k}}{2.303}\log \frac{4}{3}$
$2. \frac{2.303}{\mathrm{k}}\log \frac{3}{4}$
$3. \frac{2.303}{\mathrm{k}}\log$ $4$
$4. \frac{2.303}{\mathrm{k}}$ $\log$ $3$