Question

Three electrolytic cells A, B & C containing molten NaNO, ZnSO, and AlF, repectively are
connected in series. A steady current of 5 ampere flows through cells until 115 g of sodium
is deposited at the cathode of the cell 'A'. How long did the current flow? What mass of
Zn & Al were deposited in the respective cells?​

Answer 1

Answer:

Cell B: Ag

+

+e

−

⇌Ag at cathode.

1 mole (108 g) of Ag is deposited by 96500 C.

1.45 g of Ag will be deposited by

108

96500×1.45

=1295.6C.

Now,

Q=It

1295.6=1.5×t

t=864s

Cell A: Zn

2+

+2e

−

→Zn

2 moles of electrons (2×96500 C of current) produces 1 mole (63.5 g) of zinc.

1295.6 C of electricity will deposit

2×96500

65.3

×1295.6=0.438 g of zinc

Cell C: Cu

2+

+2e

−

→Cu

2 moles of electrons (2×96500 C) of current will produce 1 mole (63.5 g) of Cu.

1295.6 C of current will deposit

2×96500

63.5×1295.6

=0.426g of copper