Question

Vapour density of metal chloride is $77$. Equivalent weight of metal is $3$ then, its atomic weight will be :

• A. 3
• B. 6
• C. 9
• D. 12

Answer 1

The correct option is D 12

Valency of metal is $\frac{2\times \text{vapour density}}{\text{Equivalent wt of metal}+35.5}=\frac{2\times 77}{3+35.5}=\frac{154}{38.5}=4$.

The atomic weight of metal is equal to the product of the equivalent weight of metal and valency.

It is equal to $3\times 4=12$.