In which one of the following reactions, rate constant has the unit $$\mathrm{mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$$ ?

For a reaction, the value of rate constant at $$300 \mathrm{~K}$$ is $$6.0 \times 10^5 \mathrm{~s}^{-1}$$. The value of Arrhenius factor $$A$$ at infinitely high temperature is

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