Find the correct statement for the reaction:

3A → C + D

It is observed that when the initial concentration of A is 10 mol L⁻¹, the half-life of the reaction is 40 minutes, while at an initial concentration of 20 mol L⁻¹, the half-life decreases to 20 minutes.

1.  The reaction is bimolecular.

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

$\log \left(-\frac{d\left[A\right]}{d\mathrm{t<mspace\; width="1em"></mspace>}}\right)=$ $\log$ $\left(\frac{d\left[B\right]}{dt}\right)$ $+$ $0.3$ 

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 first order reaction \(\text{PCl}_5 (g) \rightarrow \text{PCl}_3 (g) + \text{Cl}_2 (g)\)  has a half-life (\(t_{0.5}\)​) of 20 minutes. What is the time required for the concentration of \(\text{PCl}_5\) to decrease to 25% of its initial concentration?

In the reaction A + B → C, if the concentration of A reduces from 4M to 2M in 1 hour, followed by a reduction 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:
\(1 .  \frac{k}{2 . 303} log \frac{4}{3}\)
\(2 .  \frac{2 . 303}{k} log \frac{3}{4}\)
\(3 .  \frac{2 . 303}{k} log\) \(4\)
\(4 .  \frac{2 . 303}{k}\) \(log\) \(3\)$\mathrm{}$