In 100g of naphthalene, `2.423g` of S was dissolved. Melting point of naphthalene `= 80.1^(@)C DeltaT_(f) = 0.661^(@)C. L_(f) = 35.7 cal//g` of naphthalene, molecular formula of sulphur is

Options

A. `S_(2)`
B. `S_(4)`
C. `S_(6)`
D. `S_(8)`

Answer

D

Explanation

`M_(2)=(1000K_(f)w_(2))/(w_(1)DeltaT_(f))=(1000w_(2))/(w_(1)DeltaT_(f))xx(RT_(0)^(2))/(1000L_(f))`
`=(1000xx2.423)/(100xx0.661)xx(2xx(353.1)^(2))/(1000xx35.7)="256 g mol"^(-1)`
If `S_(x)` is the formula, then molecular mass `x xx 32 = 56 or x = 8`.