Question

1. 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 molal depression constant of cyclohexane are 6.5°C and 20.2 K m^-1 respectively. 

2. State Henry’s Law and mention its two important applications.

3. Which of the following has higher boiling point and why? 0.1 M NaCl or 0.1 M Glucose.

Answer 1

M_B = 158 g mol^-1

2. Henry’s Law: 

The solubility of a gas in a liquid is directly proportional to the pressure of the gas.

Applications: 

• Solubility of CO₂ is increased at high pressure. 
• Mixture of He and O₂ are used by deep sea divers because he is less soluble than nitrogen.

3. 0.1 M NaCI, because it dissociates in solution and furnishes greater number of particles per unit volume while glucose being a non-electrolyte does not dissociate.