Question

Mass of zinc deposited at cathode by passing a current of 3.86 ampere for 100 minutes in molten zinc chloride is:
(atomic mass of Zn = 65.4 u)

• A. 10.5 g
• B. 12.2 g
• C. 4.5 g
• D. 7.8 g

Answer 1

The correct option is D 7.8 g

Number of Faradays passed $=\frac{3.86\times 100\times 60}{96500}=0.24$

Number of Faradays passed = number of equivalents of metal deposited at cathode

Equivalent weight of $Zn=\frac{65.4}{2}g$

Mass of zinc deposited $=0.24\times \frac{65.4}{2}g=7.8g$