When a current of \(0.5 \mathrm{~A}\) is passed for 2 hours through a molten metal salt, \(3.88…
When a current of \(0.5 \mathrm{~A}\) is passed for 2 hours through a molten metal salt, \(3.88 \mathrm{~g}\) of the metal was deposited. If atomic mass of the metals is 208 units, the oxidation state of the metal in the salt is
+1
+2
+3
+4
Solution
\(\begin{aligned}
& w=\frac{E i t}{F}=\frac{\frac{A}{n} \times i \times t}{F} \\
& \Rightarrow n=\frac{A \times i \times t}{w \times F}=\frac{208 \times 0.5 \times(2 \times 3600)}{3.88 \times 96500}=1.999 \approx 2 \\
& {[\because A=\text { atomic mass of the metal }=208 \text { unit }} \\
& i=\text { current }=0.5 \mathrm{~A} \\
& t=\text { time }=2 \text { hrs }=2 \times 3600 \mathrm{~s} \\
& E=\frac{A}{n}=\text { Equivalent mass of the metal } \\
& n=\text { valency of the metal in the salt }
\end{aligned}\)
\(\text {So, oxidation state of the metal in the salt }=+2] \text {. }\)