Question

How much charge is required for the 1 mol \( \mathrm{Al^{3+}} \) to Al?

• A. 1F
• B. 2F
• C. 4F
• D. 3F

Hint:

Number of Faradays required = number of electrons involved in the half-reaction.

Answer 1

The Correct Option is D

Concept: The charge required in electrolysis is calculated using Faraday’s laws. 1 Faraday (F) is the charge carried by 1 mole of electrons. \[ 1F = 96500 \text{ C} \]
Step 1: Write the Reduction Reaction \[ \mathrm{Al^{3+} + 3e^- \rightarrow Al} \] This shows:
1 mole of \( \mathrm{Al^{3+}} \) requires 3 moles of electrons.

Step 2: Convert Electrons to Faradays
1 mole electrons = 1 Faraday
3 moles electrons = 3 Faradays

\[ \boxed{\text{Required charge} = 3F} \]