An increase in the concentration of the reactants of a reaction leads to a change in:

1.	Heat of reaction	2.	Threshold energy
3.	Collision frequency	4.	Activation energy

Which of the following is the time required to reduce the amount of a reactant from 2.0 g to 0.2 g for a first-order reaction with rate constant \(k = 4.606 \times 10^{-3} \, \text{s}^{-1}\)?

The half-life for a zero-order reaction having 0.02 M initial concentration of reactant is 100 s. The rate constant (in mol L^–1 s^–1) for the reaction is:

1. $1.0\times {10}^{-4}$

2. $2.0\times {10}^{-4}$

3. $2.0\times {10}^{-3}$

4. $1.0\times {10}^{-2}$

What does Z_AB represent in the collision theory of chemical reactions?

A first-order reaction has a rate constant of 2.303 × 10¯³ s¯¹. The time required for 40 g of this reactant to reduce to 10 g will be
[Given that ${\log }_{10}2=0.3010$]

The unit of rate constant for a zero-order reaction is:

1. ${\mathrm{s}}^{-1}$

2. $\mathrm{mol}$ ${\mathrm{L}}^{-1}{\mathrm{s}}^{-1}$

3. $\mathrm{L}$ ${\mathrm{mol}}^{-1}{\mathrm{s}}^{-1}$

4. ${\mathrm{L}}^2{\mathrm{mol}}^{-2}{\mathrm{s}}^{-1}$

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 rate of the reaction $2{\mathrm{N}}_2{\mathrm{O}}_5\to 4{\mathrm{NO}}_2+{\mathrm{O}}_2$ can be written in three ways:

$\frac{-d\left[N_2{O}_5\right]}{dt}=k\left[N_2{O}_5\right]$

$\frac{d\left[N{O}_2\right]}{dt}=k\text{'}\left[N_2{O}_5\right]$

$\frac{d\left[O_2\right]}{dt}=k\text{'}\text{'}\left[N_2{O}_5\right]$

Find out the relationship between k and k′ and between k and k′′:

1. k′ = k, k′′= k 

2. k′= 2k; k′′= k

3. k′= 2k, k′′= k/2 

4. k′ = 2k; k′′= 2k

The rate of the reaction

2NO + Cl₂ → 2NOCl is given by the rate equation
rate = k[NO]²[Cl₂]

The value of the rate constant can be increased by: 

1. Increasing the concentration of NO
2. Increasing the concentration of Cl₂
3. Increasing the temperature
4. All of the above