Question

Hydrogen peroxide oxidises $[Fe(CN)6]^{4-}$ to $[Fe(CN)6]^{3-}$ in acidic medium but reduces $[Fe(CN)6]^{3-}$ to$[Fe(CN)6]^{4-}$ in alkaline medium. The other products formed are, respectively

• A. $ (H_2O + O_2)$ and $H_2O$
• B. $(H_2O + O_2)$ and $(H_2O + OH^{-})$
• C. $H_2O$ and $(H_2O + O_2) $
• D. $H_2O $ and $(H_2O + OH^{-})$

Answer 1

The Correct Option is C

To determine the products formed when hydrogen peroxide reacts with ferrocyanide and ferricyanide complexes in different media, we must analyze the reactions based on the medium acidity or alkalinity.

1. Reaction in Acidic Medium:
   • In an acidic medium, hydrogen peroxide acts as an oxidizing agent.
   • The chemical equation for the reaction is: H_2O_2 + 2[Fe(CN)_6]^{4-} + 2H^+ \rightarrow 2[Fe(CN)_6]^{3-} + 2H_2O.
   • In this reaction, hydrogen peroxide is reduced to water (H_2O).
   • Thus, the additional product formed is H_2O.
2. Reaction in Alkaline Medium:
   • In an alkaline medium, hydrogen peroxide exhibits reducing properties.
   • The chemical equation for this reaction can be represented as: H_2O_2 + 2[Fe(CN)_6]^{3-} + 2OH^- \rightarrow 2[Fe(CN)_6]^{4-} + O_2 + 2H_2O.
   • In this scenario, hydrogen peroxide is decomposed into oxygen (O_2) and water (H_2O).
   • The additional products formed are (H_2O + O_2).

By examining both scenarios, we conclude that in acidic conditions, the other product is H_2O, and in alkaline conditions, it is (H_2O + O_2). Therefore, the correct answer is:

Answer: In acidic medium: H_2O; in alkaline medium: (H_2O + O_2).