Which of the following reactions is not of the first order?

Which of the following reactions is not of the first order?
  1. Inversion of sucrose in the presence of acid
  2. Acid-catalyzed hydrolysis of ethyl acetate
  3. Hydrolysis of tertiary butyl halide using alkali
  4. Oxidation of $\mathrm{I}^{-}$ ion by $\mathrm{S}_{2} \mathrm{O}_{8}^{2-}$ ion

Solution

It is a second order reaction, first order both w.r.t $\mathrm{S}_{2} \mathrm{O}_{8}{ }^{2-}$ and $\mathrm{I}^{-}$.
$\therefore r=k\left[\mathrm{~S}_{2} \mathrm{O}_{8}^{2-}ight]\left[\mathrm{I}^{-}ight]$
All other options are of first order reaction.

Asked in: JEE-TOPICTESTS-CHEMISTRY

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