Question

calculate the mass of aluminium that would be deposited on the cathod when a current of 3.5A is passed through a molten salt for 120 minutes

Answer 1

Answer:

3 amperes is 5 coulombs per second, 3 C/s

So the total charge in 30 minutes is Q=3C/s×15min×60s/min=2700C

Then the number of moles of copper plated out (n) is:

n= Q\zF

where z is the number of electrons in the half-cell reaction (in this case, 2)

and F is the Faraday constant = 96,485/mol

So, n= 2700\(2×96485)=0.0139 mol

And this is 63.546×0.0139=4.54g

So 4.54 grams are plated deposited at the cathode.