UPSEE Solved Model Paper 7

Given:
Weight percentage of chlorine = 71%
Vapour density = 50
Vapour density is given by:
Vapour density = Molecular Mass/2
Substituting the value of vapour density, we get
50 = Molecular Maas /2
Molecular Mass of metal chloride = 50 x 2 = 100
Now,
Chlorine is 71% by weight or 71 g/mol.
Thus,
Atomic weight of metal = Molecular mass of metal
chloride - Weight of chlorine
= 100 - 71
= 29 g/mol
Hence, option 'A' is correct.