(a) Menthol is a crystalline substance with peppermint taste. `A.6.2%` solution of menthol in cyclohexane freezes at `-1.95^(@)C.` Determine the formula mass of menthol. The freezing point and molar depression constant of cyclohexane are `6.5 ^(@)C and 20.2Km ^(-1),` respectively.
(b) State Henry's Law and mention its two important applications.
(c ) Which of the following has higher boiling point and why ? `0.1M NaCl or 0.1 M` Glucose

Explanation

(a)` Delta T_(f) = K _(f) m= (W _(B))/(M _(B))xx (1000)/(W _(A))`
`8.45 =20.3 K kg mol ^(-1) xx (6.2 g )/( M _(B)) xx (1000)/(93.8kg`
` M _(B)=158 mol ^(-1)`
(b) Henry.s Law: The solubility of gas in a liquid is directly proporational to the pressure of the gas.
Applications:
1. Solubility of `CO_(2)` is increased at high pressurre.
2. Mixture of He and `O_(2)` are used by deep sea divers because he is less soluble than nitrogen.
(c ) `0.1M NaCl,` because it dissociates in solution and furnishes greater number of particles per unit volume while glucose being a non-electrolyte does not dissociate.