The reaction $A \to P$ follows first order kinetics. The percentage of $A$ left after $3$ half-lives is

If compound $A$ reacts with $B$ following first order kinetics with rate constant $2.011 \times 10^{-3} \ s^{-1}$. The time taken by $A$ (in seconds) to reduce from $7 \ g$ to $2 \ g$ will be $.........$ (Nearest Integer) $[\log 5=0.698, \log 7=0.845, \log 2=0.301]$

$A$ first order reaction takes $40 \ min$ for $30 \%$ decomposition. Calculate $t_{1/2}$.

If the concentration is expressed in $mol \ L^{-1}$,the unit of the rate constant for a first-order reaction is........

For a first-order reaction,the ratio of the time required for $99.9\%$ completion to the time required for $50\%$ completion is:

For a first-order reaction,the concentration decreases from $800 \ mol/dm^3$ to $50 \ mol/dm^3$ in $2 \times 10^4 \ s$. What is the rate constant of the reaction?