Q1.An element X forms an Oxide with formula "X₂O₃" :-

(a)State the valency of "X".

(b)Write the formula of chloride of "X".

(c)Sulphate of "X".

(a) In a molecular formula, the valency of a metal is written at the subscript of non-metal and vice-versa.So the, valency of X in X₂O₃ is 3.
(b) The valency of chlorine is 1 and the valency of X is 3.So, the formula for chloride of X is XCl₃
(c) The valency of sulphate ion is 2 and the valency of X is 3.So formula of sulphate of X is X₂(SO₄)₃