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JEE Advanced Chemistry Electrochemistry 2024 JEE Advanced 2024 (Paper 2)

JEE Advanced Chemistry Question (2024) — Solution

Question

An aqueous solution of hydrazine ( N _2 H _4 ) is electrochemically oxidized by O _2, thereby releasing chemical energy in the form of electrical energy. One of the products generated from the electrochemical reaction is N _2( ~g ). Choose the correct statement(s) about the above process :

Options

  1. A. OH ^ - ions react with N _2 H _4 at the anode to form N _2( ~g ) and water, releasing 4 electrons to the anode.
  2. B. At the cathode, N _2 H _4 breaks to N _2( ~g ) and nascent hydrogen released at the electrode reacts with oxygen to form water.
  3. C. At the cathode, molecular oxygen gets converted to OH ^ - .
  4. D. Oxides of nitrogen are major by-products of the electrochemical process.

Answer

C. At the cathode, molecular oxygen gets converted to OH ^ - .

Step-by-step solution

\( Oxidation \\ (Anode) -2 N_2H_4 + Reduction \\ (Cathode) 0 O_2 0 N_2 + H _2 O ^ -2 \) At anode: \( N _2 H _4+4 OH ^ - N _2+4 H _2 O +4 e^ - \) At cathode: \( O _2+2 H _2 O +4 e^ - 4 OH ^ - \) Complete reaction: \( N _2 H _4+ O _2 N _2+2 H _2 O \) Statements (A) and (C) are correct.

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