This question was poorly attempted as most respondent candidates were not able to relate the mass of copper deposited to the quantity of charge passed through the voltameter and then the amount of charge required to deposited a mole of copper.
ml = mr =
Q l Q r
[Q1 = lt]
Q r = 2 x 96500 C
mr = 0.625 x 10-3 x 2 x 96500
1.57 x 20 x 60
= 0.064 kg
The expected answer is
Q = It
= 1.57 x 20 x 60
= 1884C
OR
1884 C 0.625 x 10-3
12 x 96500 C
2 x 96500 x 0.625 x 10-3
1884
0.064 kg
