The vapour density of a chloride of an element is `39.5`. The equivalent mass of the element is `3.82`. The atomic weight of the element is

Options

A. `15.28`
B. `7.64`
C. `3.82`
D. `11.46 `

Answer

B

Explanation

Mol. Mass of metal chloride `(MCl _(x)) := M + x + 35.5 = 2 xx VD = 2 xx 39.5 = 79.0`
Let valency of metal be .x. and atomic mass of element = eq. mass `xx x`
`MCl _(x) = (3. 82 xx x) + (x xx 35.5) = 79 implies x = ( 79)/(3 .82 + 35.5) = 2`
Atomic weight = eq. mass `xx x = 3. 82 xx 2 = 7. 64`