The half-life of a first order reaction having rate constant $K = 1.7 \times 10^{-5} \ s^{-1}$ is ........ $hr$.

For a first-order reaction,the ratio of $t_{3/4}$ to $t_{1/2}$ is ...

Time required for $90 \%$ completion of a first order reaction is '$x$' minute. Calculate the time required to complete $99.9 \%$ of the reaction at the same temperature.

For the reaction $R \rightarrow P$,the half-life is independent of the initial concentration of the reactant,$R$. Which one of the following graphs is not correct for this reaction?

In a first order reaction,the concentration of the reactant decreases from $0.8 \ M$ to $0.4 \ M$ in $15 \ min$. The time taken for the concentration to change from $0.1 \ M$ to $0.025 \ M$ is .......... $min$.

In a first order reaction,if the concentration of reactant drops from $0.8 \ mol \ L^{-1}$ to $0.4 \ mol \ L^{-1}$ in $15$ minutes,what is the time required to drop the concentration from $0.1 \ mol \ L^{-1}$ to $0.025 \ mol \ L^{-1}$?