The rate constant $$k_1$$ and $$k_2$$ for two different reactions are $$10^{16} \times e^{-2000 / T}$$ and $$10^{15} \times e^{-1000 / T}$$ respectively. The temperature at which $$k_1=k_2$$ is

For $$n$$th order of reaction, half-life period is directly proportional to

Half-life of a reaction is found to be inversely proportional to the fifth power of its initial concentration, the order of reaction is

A first order reaction is half completed in $$45 \mathrm{~min}$$. How long does it need $$99.9 \%$$ of the reaction to be completed?