Question

The solution of a salt of a metal of atomic mass $112$ was electrolysed for $15$ minutes with a current of $1.5ampere$. The mass of the metal deposited was $0.788g$. Find the valency of the metal.

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

Answer: (B)

2

Given mass$=0.788g$

Current(I) $=1.5ampere$

Time(t)$=15min=900sec$

Atomic Mass$=112$

Formula:-

Mass$=\frac{E}{F}\times I\times t$ [$E=EquivalentWeight,F=Faraday=96500C,1C=1ampere\times 1sec$]

$\therefore 0.788g=\frac{E}{96500C}\times 1.5\times 900\left(C\right)$

$\therefore \frac{0.788\times 96500}{1.5\times 900}=E$

$\therefore E=56.3$

Equivalent Weight$=\frac{Atomicmass}{Valency}$

$\therefore Valency=\frac{Atomicmass}{Equivalentweight}=\frac{112}{56.3}=2$