The molecular weight of chloride of an element is 79. The `Ew` of the elements is 3.82. The atomic weight of the elements is

Options

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

Answer

B

Explanation

Molar mass `= 2 xx` vapour density `= 2 xx 39.5 = 79`
Let x be valency of element `rArr` Formula of chloride is MClx
`rArr (3.82 xx x) + 35.5 x = 79 rArr x = 2 rArr` Atomic weight of element `= 3.82 xx 2 = 7.64`