Calculate the time in seconds required to reduce the concentration of reactant to half of initial concentration for a first order reaction if the rate constant is $1.386 \times 10^{-3} \ s^{-1}$. (in $s$)

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

The decomposition of benzene diazonium chloride is a first order reaction. The time taken for the decomposition of $\frac{1}{4}$ and $\frac{1}{10}$ of its initial concentration are $t_{1/4}$ and $t_{1/10}$ respectively. The value of $\frac{t_{1/4}}{t_{1/10}} \times 100$ is (Given: $\log 2 = 0.3, \log 3 = 0.477$)

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.

In a first order reaction,the concentration of the reactant decreases from $0.6 \ M$ to $0.3 \ M$ in $15 \ min$. The time taken for the concentration to change from $0.1 \ M$ to $0.025 \ M$ in minutes is

If the rate constant for a first order reaction is $k$,then find the time required for completion of $80 \%$ of the reaction.