For which of the following graphs is the intersection (y-intercept) zero?

For a first-order reaction $A \rightarrow B$,the rate of reaction is $2.0 \times 10^{-5} \, mol \, L^{-1} \, s^{-1}$ when the concentration of the reactant is $0.01 \, M$. The half-life of the reaction is ........ seconds.

Which one of the following graphs is not applicable for a $1^{st}$ order reaction $(R \rightarrow P)$?

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?

If $k$ is the rate constant and $t$ is the time,then the degree of dissociation for a substance undergoing decay with first-order kinetics is:

If $60\%$ of a first order reaction was completed in $60 \ min$,$50\%$ of the same reaction would be completed in approximately $.......... \ min.$
$(\log \, 4 = 0.60, \, \log \, 5 = 0.69)$