Question

When electricity is passed through a solution of $AlC{l}_3$, 13.5 g of Al is deposited. The number of Faradays (charge) must be:

• A. 1
• B. 1.5
• C. 0.5
• D. 2

Answer 1

The correct option is D 2

$AlC{l}_3\to A{l}^{3+}+3C{l}^{-}$
Using faraday's law of electrolysis
$w=\frac{E.i.t}{F}$
where,
w = amount of Al deposited
F= faraday's constant
i = current supplied
t = total time for which current is supplied
E = equivalent weight = Molar mass/ no of electron transfer per mole
put up in equation;
$13.5=\frac{\frac{27}{3}i.t}{F}$
$Q=i.t=1.5F$