In a first order reaction, concentration of reactant is reduced to (1/8)^th of concentration in 23.03 minutes. What is half-life period of reaction?

For the reaction $$2 \mathrm{NO}+\mathrm{Cl}_2 \rightarrow 2 \mathrm{NOCl}$$

What is the relation between $$\frac{\mathrm{d}[\mathrm{NO}]}{\mathrm{dt}}$$ and $$\frac{\mathrm{d}[\mathrm{NOCl}]}{\mathrm{dt}}$$ ?

In a first order reaction concentration of reactant decreases from 20 m mol to 10 m mol in 1.151 min. What is rate constant?

Which type of reaction order is followed by radioactive processes?