An element, X, forms a volatile hydride XH3 with a vapour density of 17.0. The…

An element, X, forms a volatile hydride XH₃ with a vapour density of 17.0. The relative atomic mass of X is?
(H = 1)

Correct Answer: Option 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