Question

Electrolysis of 600 mL aqueous solution of NaCl for 5 min changes the pH of the solution to 12. The current in Amperes used for the given electrolysis is ________________________. (Nearest integer).

Hint:

Use Faraday’s laws of electrolysis to relate charge, time, and current.

Answer 1

Correct Answer: 1.93

Using Faraday's law: \[ \text{Charge} (Q) = I \times t \] Hydroxide ion (\( OH^- \)) concentration at \( pH = 12 \): \[ [OH^-] = 10^{-2} \, {M} \] Moles of \( OH^- \) in 0.6 L: \[ n = 0.6 \times 10^{-2} = 6 \times 10^{-3} \, {moles} \] Charge required: \[ Q = n \times F = 6 \times 10^{-3} \times 96500 \] \[ = 579 \, C \] Current: \[ I = \frac{Q}{t} = \frac{579}{300} \approx 1.93  \, A \]