Question

(laws of Faraday)

two plates of copper (one anode and the other cathode),one plate has as twice mass as the other one, find their masses if you know that after passing a current (3 amper) in 1000 seconds ,their masses become equal

Answer 1

The reactions that will be going to occur at anode and cathode are given below

Charge passed = Current * Time = 3 amp * 1000 = 3000C

Molar mass of Copper = 63.5 gm/mol

For deposition of 1 mole of Copper, we required 2 * 96500C, since copper will be present in +2 oxidation state

Mass of copper deposited = 3000/(2*96500) * 63.5 = 0.98704 grams

let the mass of cathode plate be x

then mass of anode plate will be 2x

Now masses after deposition will be same

2x - 0.98704 = x + 0.98704

x = 1.9740 grams

Mass of cathode plate = 1.9740 grams

Mass of anode plate = 3.94816 grams