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

If concentration of reactant ' $A$ ' is increased by 10 times, rate of reaction increases 100 times. What is order of reaction if rate law is $r=k[A]^r$ ?

What is order and molecularity of following reaction?

$$ \mathrm{NO}_{2(\mathrm{~g})}+\mathrm{NO}_{2(\mathrm{~g})} \longrightarrow 2 \mathrm{NO}_{(\mathrm{g})}+\mathrm{O}_{2(\mathrm{~g})} $$

Half life of a first order reaction is 3 minute. What is the time required to reduce the concentration of reactant by $90 \%$ of its initial concentration?