Which of the following is a practical application of freezing point depression?

• A. Electrolysis of water to produce hydrogen gas
• B. Distillation of water to remove impurities
• C. Using activated carbon to filter water
• D. Using salt to melt ice on roads during winter

Answer: (D)

Verified step by step guidance

1. Understand the concept of freezing point depression: it is a colligative property where the addition of a solute to a solvent lowers the freezing point of the solvent.
2. Identify practical applications where lowering the freezing point is useful, such as preventing water from freezing at 0°C by adding substances like salt.
3. Recognize that adding salt to ice on roads causes the ice to melt at a temperature below the normal freezing point of water, making roads safer in winter.
4. Compare the given options and note that electrolysis, distillation, and activated carbon filtration do not involve changing the freezing point of water.
5. Conclude that the practical application of freezing point depression is best exemplified by using salt to melt ice on roads during winter.