Question

When an aqueous solution containing gold (III) salt is electrolyzed, metallic

gold is deposited at the cathode and oxygen gas is generated at the anode. If

9.26 g of Au is deposited at the cathode, calculate the volume (in liters) of O2

generated at 23°C and 747 mmHg.

Answer 1

Mole ratio for discharge is:

Au : O

2 : 3.

Moles of oxygen discharged was

3/2 × 9.26 = 13.89 moles

Volume of oxygen :

At RTP, molar gas volume is 24dm³

Volume of 13.89 moles of oxygen is

13.89×24=333.36litres

P1V1/T1=P2V2/T2

296×747/V2 = 298×760/333.36

And = 325.46 litres