When a solid element is reacted with `Cl_(2)`, a gaseous chloride of vapour density, `68.75` is formed. If this reaction is performed at constant temperature and pressure. The volume of the system is reduced by `1//3`. If `E =` equivalent mass of element, the volume of `(12)/(31)XE` is

Answer

4

Explanation

`M(s) + (x)/(2) Cl_(2) (g) rarr MCl_(x)(g)`
let `V_(1) = V rArr V_(2) = (2)/(3) V_(1)`
According to Avogadro's law, `(n_(1))/(n_(2)) = (V_(1))/(V_(2))`
`(x)/(2) = (3)/(2) rArr x = 3`
molar mass `= 2x v.d = 137.5`
`M + 35.5 xx 3 = 137.5 ( :' M =` atomic mass of element)
`rArr M = 31 :. E = (31)/(3) rArr (12)/(31) xx E = (12)/(31) xx (31)/(3) = 4`