Question

Three Ampere current was passed through an aqueous solution of an unknown salt of metal M for 1hour. 2.977 g of $M^{n +}$ was deposited at cathode. The value of n is (At wt. of M =106.4).

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

Answer: (D)

4

Answer 2

$\mathbf{M}^{\mathbf{n +}}\mathbf{+ n}\mathbf{e}^{\mathbf{-}}\mathbf{\rightarrow M}$; $\frac{\mathbf{W}}{\mathbf{E}}\mathbf{=}\frac{\mathbf{I}\mathbf{\times}\mathbf{t}}{\mathbf{96500}}$

$\Rightarrow$ $\frac{\mathbf{2.977}}{\mathbf{106.4/n}}\mathbf{=}\frac{\mathbf{3 \times 1 \times 60 \times 60}}{\mathbf{96500}}$ (1 hour = 60×60); $n = 4.$