Question

How many hours does it take to reduce 3 moles of Fe³⁺ to Fe²⁺ with 2.0 A current intensity?

Answer 1

Given:

\[\ce{Fe^{3+} + e^- -> Fe^{2+}}\]

For 1 mole of Fe³⁺, 1 mole of e⁻ is required.

∴ For 3 moles of Fe³⁺, 3 moles of e⁻ are required.

1 Faraday (F) = 96500 C

Current (I) = 2.0 A

Total charge (Q) needed = 3 × 96500 C = 289500 C

Formula:

Q = I × t

289500 = 2 × t

t = `(289500)/(2)`

t = 144750 seconds

∴ `t = 144750/3600`    ...(1 hour = 3600 seconds)

t = 40.2 hrs