Which reaction is NOT a redox reaction?

• A

  $2 \mathrm{KClO}_3+\mathrm{I}_2 \rightarrow 2 \mathrm{KIO}_3+\mathrm{Cl}_2$
• B

  $\mathrm{H}_2+\mathrm{Cl}_2 \rightarrow 2 \mathrm{HCl}$
• Correct answer
  C

  $\mathrm{BaCl}_2+\mathrm{Na}_2 \mathrm{SO}_4 \rightarrow \mathrm{BaSO}_4+2 \mathrm{NaCl}$
• D

  $\mathrm{Zn}+\mathrm{CuSO}_4 \rightarrow \mathrm{ZnSO}_4+\mathrm{Cu}$

Solution

(3) $\mathrm{BaCl}_2^{-1}+\mathrm{Na}_2^{+1} \mathrm{SO}_4^{-2} \longrightarrow \stackrel{+2}{\mathrm{BaSO}_4+2 \mathrm{NaCl}^{-1}}$ This is not a redox reaction as there is no change in oxidation state.

Hence, the correct answer is option: 'C'.