Question:medium

The electrolyte used in $H_2 - O_2$ fuel cell is ________.

Show Hint

Remember that "Alkaline Fuel Cells" (AFCs) specifically use aqueous potassium hydroxide as the electrolyte because it has the highest conductivity among the alkali metal hydroxides.
  • aqueous KCl
  • aqueous KOH
  • aqueous HCl
  • aqueous $KNO_3$
Show Solution

The Correct Option is B

Solution and Explanation

Step 1: Understanding the Concept:
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (hydrogen) and an oxidizing agent (oxygen) into electricity through a pair of redox reactions.
Step 3: Detailed Explanation:
In a standard alkaline \(H_2 - O_2\) fuel cell, the electrolyte used is a concentrated aqueous solution of potassium hydroxide (\(KOH\)) or sodium hydroxide (\(NaOH\)).
Aqueous \(KOH\) is preferred because of its high ionic conductivity.
The electrodes are made of porous carbon impregnated with catalysts like platinum.
The hydroxide ions (\(OH^-\)) migrate through the electrolyte to complete the circuit.
Step 4: Final Answer:
The correct electrolyte is aqueous \(KOH\).
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