$A$ substance (initial concentration $= a$) reacts according to zero order kinetics. The time taken for the completion of reaction is nearly

Which of the following is true for a zero order reaction?

The rate constant for a zero order reaction is $3 \times 10^{-2} \ mol \ L^{-1} \ s^{-1}$. After $25 \ s$,if the concentration of the reactant is $0.5 \ M$,then the initial concentration of the reactant is ............ $M$.

The unit of the velocity constant in case of zero order reaction is

What is the unit of rate constant for the zero order reaction?

The rate constant of the reaction $A \rightarrow B$ is $0.6 \times 10^{-3} \, mol \, L^{-1} \, s^{-1}.$ If the concentration of $A$ is $5 \, M,$ then the concentration of $B$ after $20$ minutes is ......... $M.$