Answer:
The molecular formula of an ascenapthalene is [tex]C_{12}H_{10}[/tex]
Explanation:
[tex]\Delta T_b=K_b\times m[/tex]
[tex]\Delta T_b=K_b\times \frac{\text{Mass of acenapthalene}}{\text{Molar mass of acenapthalene}\times \text{Mass of chloroform in Kg}}[/tex]
where,
[tex]\Delta T_f[/tex] =Elevation in boiling point = [tex](62.5-61.7)^oC=0.8^oC[/tex]
Mass of acenapthalene = 0.515 g
Mass of [tex]CHCl_3[/tex] = 15.0 g = 0.015 kg (1 kg = 1000 g)
[tex]K_b[/tex] = boiling point constant = 3.63 °C/m
m = molality
Now put all the given values in this formula, we get
[tex]0.8^0C=3.67 ^oC/m\times \frac{0.515}{\text{Molar mass of acenapthalene}\times 0.015kg}[/tex]
[tex]\text{Molar mass of acenapthalene}=155.7875 g/mol[/tex]
Let the molecule formula of the Acenapthalene be [tex]C_{6n]H_{5n}[/tex]
[tex]6n\times 12 g/mol+5n\times 1 g/mol=155.7875 g/mol[/tex]
n = 2.0
The molecular formula of an ascenapthalene is [tex]C_{12}H_{10}[/tex]
