Instantaneous rate of a reaction is $-\frac{1}{2}…
Instantaneous rate of a reaction is $-\frac{1}{2} \frac{\mathrm{d}[\mathrm{x}]}{\mathrm{dt}}=-\frac{\mathrm{d}[\mathrm{y}]}{\mathrm{dt}}=\frac{1}{2} \frac{\mathrm{d}[\mathrm{z}]}{\mathrm{dt}}$, identify the reaction.