In a first order reaction,the concentration of the reactant decreased from $0.4 \, M$ to $0.1 \, M$ in $20 \, \min$. The rate constant of the reaction will be:

What is the half-life time of a first-order reaction if the initial concentration of the reactant is $0.01 \ mol \ L^{-1}$ and the rate of reaction is $0.00352 \ mol \ L^{-1} \ minute^{-1}$?

In a first order reaction,the concentration of reactant decreases from $800 \ mol/dm^3$ to $50 \ mol/dm^3$ in $2 \times 10^2 \ s$. The rate constant of the reaction in $s^{-1}$ is:

The plot of $t_{1/2}$ versus $[R]_0$ for a reaction is a straight line parallel to the $x$-axis. The unit for the rate constant of this reaction is:

An organic compound undergoes first-order decomposition. The time taken for its decomposition to $1/8$ and $1/10$ of its initial concentration are $t_{1/8}$ and $t_{1/10}$ respectively. What is the value of $\frac{t_{1/8}}{t_{1/10}} \times 10$? (Given: $\log_{10} 2 = 0.3$)

The slope of a graph $\log [A]_t$ versus '$t$' for a first-order reaction is $-2.5 \times 10^{-3} \,s^{-1}$. Find the rate constant of the reaction.