Question

On passing a current through a $\text{KCl}$ solution, 19.5 g of potassium is deposited. If the same quantity of electricity is passed through a solution of aluminium chloride, the amount of aluminium deposited is :

• A. 4.5g
• B. 9.0g
• C. 13.5g
• D. 27g

Answer 1

Answer: (A)

According to Faradays second law of electrolysis, the amount of different substances deposited by the passage of same quantity of electricity are proportional to their chemical equivalent weights. $W\propto E$ $\frac{W_1}{W_2}=\frac{E_1}{E_2}$ $W_{KCl}=19.5g;E_{K^{+}}=39$ $W_{AlC{l}_3}=?;E_{A{l}^{3+}}=\frac{27}{3}=9$ then , $\frac{19.5}{x}=\frac{39}{9}$ $x=\frac{19.5\times 9}{39}=4.5g$ So, 4.5 g of aluminium is deposited.