For a first order reaction, the half-life is $5 \text{ hour}$. What time is required to reduce $10 \text{ g}$ of reactant to $2.5 \text{ g}$ (in $\text{ hour}$)?

The rate constant of a first order reaction is $3 \times 10^{-6} \ s^{-1}$. If the initial concentration is $0.10 \ M$,the initial rate of reaction is:

The time required for completion of $93.75 \%$ of a first order reaction is $x$ minutes. The half life of it (in minutes) is

The reaction,$X \to$ product follows first order kinetics. In $40 \, min$ the concentration of $X$ changes from $0.1 \, M$ to $0.025 \, M$. Then the rate of reaction when concentration of $X$ is $0.01 \, M$ is:

The reaction,$N_2O_5 \longrightarrow 2NO_2 + \frac{1}{2} O_2$ is of first order for $N_2O_5$ with rate constant $6.2 \times 10^{-4} \ s^{-1}$. What is the value of rate of reaction when $[N_2O_5] = 1.25 \ mol \ L^{-1}$?

The rate constant of a reaction is $0.69 \times 10^{-1} \ min^{-1}$ and the initial concentration is $0.2 \ mol \ L^{-1}.$ The half-life period is ........ $\sec$