Fuel cell involves ______.

The correct answer is Option (1) → The reaction of $H_2$ with $O_2$ to give $H_2O$

A fuel cell is an electrochemical cell that converts the chemical energy of a fuel directly into electrical energy through redox reactions.

The most common example is the hydrogen–oxygen fuel cell, where hydrogen gas acts as the fuel and oxygen gas acts as the oxidizing agent.

In this cell, hydrogen and oxygen react electrochemically to form water, and during this reaction electrical energy is produced.

The overall reaction in a hydrogen–oxygen fuel cell is:

2H₂ + O₂ → 2H₂O

At the anode, hydrogen is oxidized:

H₂ → 2H⁺ + 2e⁻

At the cathode, oxygen is reduced:

O₂ + 4H⁺ + 4e⁻ → 2H₂O

Thus, the fuel cell operates by the reaction of hydrogen with oxygen to produce water while generating electricity.

Option-wise Explanation

Option 1: The reaction of H₂ with O₂ to give H₂O

This is correct. Hydrogen and oxygen react in a hydrogen–oxygen fuel cell to produce water and electrical energy.

Option 2: The splitting of H₂O to give O₂

This is incorrect. Splitting of water is part of electrolysis of water, not a fuel cell reaction.

Option 3: The splitting of H₂O to give H₂

This is incorrect. Production of hydrogen from water occurs during electrolysis, not in a fuel cell.

Option 4: The reaction of H₂ and H₂O to give O₂

This is incorrect because hydrogen does not react with water to produce oxygen in a fuel cell.