Chemical Kinetics

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 \(\frac{\mathrm{d}[\mathrm{NOCl}]}{\mathrm{dt}}\) ?