Question

$0.3605$g of a metal is deposited on the electrode by passing $1.2$ amperes of current for $15$ minutes through its salt solution. The atomic weight of the metal is $96$. What is the valency of the metal?

Answer 1

Given: Weight 'w' of the metal$=0.3605$g
Current $=1.2$amp.
time$=15$min$=15\times 60$sec.
Atomic weight of metal$=96$.
According to Faraday's first law of electrolysis:
Electrochemical equivalent $Z=\frac{w}{I\times t}$
$=\frac{0.3605}{1.2\times 15\times 60}$

$=3.34\times {10}^{-4}$g $C^{-1}$

Valency$=\frac{Atomicwt.}{Equivalentwt.}$

$=\frac{96}{3.34\times {10}^{-4}\times 96500}$

$=2.98\simeq 3$ $(\because$ Equivalent $wt=Z\times F$)
$\because$ Valency of metal is $3$.