How long will it take to electroplate 56.9 g of gold using a current of 2.0 A from a Au3+ solution?

Molar mass of Au = 197.0 g/mol
No. of moles of Au = (56.9 mol) / (197.0 g/mol) = 0.2888 mol

Au³⁺(aq) + 3e⁻ → Au(s)
Mole ratio e⁻ : Au = 3 : 1
No. of moles of e⁻ = (0.2888 mol) × 3 = 0.8664 mol

Each mole of e⁻ carries 96500 C (1 F) of electricity.
Amount of electricity, Q = (96500 C/mol) × (0.8664 mol) = 83600 C

Time taken, t = Q/I = (83600 C) / (2.0A) = 41800 s = 11.61 h