The rate constant for a first order reaction is $4.606\times {10}^{-3} s^{-1}$. The time required to reduce 2.0 g of the reactant to 0.2 g is:

1.	200 s	2.	500 s
3.	1000 s	4.	100 s

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

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. $1.0\times {10}^{-2}$

For a reaction, activation energy $E_a=0$ and the rate constant at 200 K is    1.6 $X$ ${10}^6{s}^{-1}$. The rate constant at 400K will be [Given that gas constant, R=8.314 J $K^{-1}$ $mo{l}^{-1}$]

1.  3. 2 x 10⁴ s^-1
2. 1.6 x 10⁶s^-1

3. 1.6 x10³ s^-1

4. 3.2 x 10⁶ s^-1

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

1. 230.3 s

2. 301 s

3. 2000 s

4. 602 s

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:

$\frac{-d\left[N_2{O}_5\right]}{dt}=k\left[N_2{O}_5\right]$
$\frac{d\left[N{O}_2\right]}{dt}=k\text{'}\left[N_2{O}_5\right]$
$\frac{d\left[O_2\right]}{dt}=k\text{'}\text{'}\left[N_2{O}_5\right]$

The relationship between k and k′ and between
k and k′′ are-

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

A 300-gram radioactive sample has a half-life of 3 hours. After 18 hours the remaining quantity will be:

1. 4.68 gram

2. 2.34 gram

3. 3.34 gram

4. 9.37 gram