Question

A current of 2.0 A passed for 5 hours through a molten metal salt deposits 22.2 g of metal (At. wt. = 177). The oxidation state of the metal in the metal salt is:

• A. + 1
• B. + 2
• C. + 3
• D. + 4

Answer 1

The correct option is C

+ 3

$\frac{\text{Q}}{\text{F}}=\text{moles}\times {\text{n}}_{\text{f}}$

$\frac{\text{i}\times \text{t}}{\text{F}}=\text{moles}\times {\text{n}}_{\text{f}}$

$\frac{2\times 5\times 3600}{96500}=\frac{22.2}{177}\times {\text{n}}_{\text{f}}$

$\Rightarrow {\text{n}}_{\text{f}}\approx 3$

Thus, oxidation state of metal in the metal salt is +3.