Question

The vapor pressure curve of the mixture of ethanol and acetone is higher than its constituents because:

• A. Weakening of interactions between molecules takes place
• B. Strengthening of interactions between molecules takes place
• C. New hydrogen bonds are formed
• D. Molecules are not able to escape from the solution

Hint:

In mixtures of liquids with different intermolecular forces, the weakening of these interactions can cause an increase in vapor pressure because molecules are more easily able to escape from the liquid into the vapor phase.

Answer 1

The Correct Option is A

In a mixture of ethanol and acetone, the vapor pressure curve is higher than that of the individual pure liquids. This behavior is observed due to the weakening of interactions between molecules of the components in the mixture. This leads to a situation where molecules of both ethanol and acetone can more easily escape into the vapor phase, which increases the total vapor pressure of the mixture. The key points to consider: - Ethanol and acetone have different intermolecular forces, with ethanol capable of hydrogen bonding. However, when mixed, the interactions between ethanol and acetone molecules are weaker than the interactions within the pure liquids. - As a result, the molecules experience less resistance to escaping the liquid phase, resulting in a higher vapor pressure. In contrast: - Strengthening of interactions would lead to a decrease in vapor pressure, as molecules would be less likely to escape. - New hydrogen bonds may be formed between ethanol and acetone, but this is not the primary reason for the higher vapor pressure. - Molecules not being able to escape would lead to lower vapor pressure, not higher.
Thus, the correct answer is Weakening of interactions between molecules takes place.