An element, X, forms a volatile hydride XH3 with a vapour density of 17.0. The relative atomic mass of X is?
(H = 1)
- 34.0
-
31.0
- 20.0
- 14.0
The correct answer is: B
Explanation
Molecular Mass = Vapour density x 2 = 17.0 x 2 = 34.0∴ Relative Atomic Mass of X in XH3 = 34 - 3
= 31.0 ∴ x = 31.0