Equivalent weight of an element ‘X’ is 3. If vapour density of volatile chloride of ‘X’ is 77, find out the number of chlorine atoms combine with element ‘X’ to form a molecule.

Equivalent weight of chloride of ‘X’ = Equivalent weight. of Cl + Equivalent weight of ‘X’.

                                                       $=35.5+3=38.5$

Molecular weight of chloride = 2 $\times$ Vapour density

                                             $=2\times 77$ $=\text{ 154}$

Valency of element ‘X’ $=\frac{molecularweight}{equivalentweight}$$=\frac{154}{38.5}=4$ 

Valency of chlorine = 1

Molecular formula $\underset{4}{X}\underset{1}{Cl}=XC{l}_4$

Number of chlorine atoms combined = 4