After how many seconds will the concentration of the reactants in a first order reaction be halved,if the decay constant is $1.155 \times 10^{-3} \, \sec^{-1}$?

$A$ first order reaction takes $23.03 \ minutes$ for $20 \%$ decomposition. Calculate its rate constant.

The reaction $2A \rightarrow 2B + C$ has a rate constant of $1.2 \times 10^{-2} \ s^{-1}$. Which of the following is correct?

$A$ and $B$ decompose via first order kinetics with half-lives $54.0 \, min$ and $18.0 \, min$ respectively. Starting from an equimolar non-reactive mixture of $A$ and $B$,the time taken for the concentration of $A$ to become $16$ times that of $B$ is ...... $min.$ (Round off to the Nearest Integer).

The half-life for the decomposition of gaseous compound $A$ is $240 \ s$ when the initial gaseous pressure is $500 \ Torr$. When the initial pressure is $250 \ Torr$,the half-life is found to be $4.0 \ min$. The order of the reaction is....... (Nearest integer)

If the rate constant for a first order reaction is $k$,the time $(t)$ required for the completion of $99\%$ of the reaction is given by: