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Q.
For a given reaction $t_{1/2}=\frac{1}{Ka}$The order of reaction
Chemical Kinetics
Solution:
$t_{1/2}=\frac{1}{Ka}$ for second order reactions
$t_{1/2}=\frac{1}{K\left(a\right)}\Rightarrow t_{1/2}\propto\frac{1}{\left[a\right]^{1}}$
$\Rightarrow t_{1/2}\propto\left[a\right]^{-1}$
Also $t_{1/2}\propto\left[a\right]^{1-n}$
$\left[a\right]^{n-1}=\left[a\right]^{-1}\Rightarrow 1-n=-1=n=2$