Which of the following liquid pair shows a positive deviation from Raoults law?a)water-nitric acidb)benzene-methanolc)acetone-chloroformd)water-hydrochloric acidCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

Positive deviation indicates weaker intermolecular forces of attractions between different components in the mixture than attractions in the pure individual components. In all of the above mixtures, except Benzene - methanol, the total vapor pressure of the mixture is less than expected i.e., show negative deviation, since the attraction forces are stronger when compared to those in pure liquids. However, in Benzene - methanol mixture the intermolecular forces of attractions are weaker than those in pure liquids. Hence, this mixture shows positive deviation.

Answer

Positive Deviation from Raoult's Law:

Raoult's law states that the vapor pressure of a solution is directly proportional to the mole fraction of solvent in the solution. When a solution deviates from Raoult's law, it can exhibit either a positive or negative deviation. In the case of a positive deviation, the observed vapor pressure of the solution is higher than that predicted by Raoult's law.

Explanation:
- Pair b: Benzene-Methanol
- In the benzene-methanol pair, benzene is a non-polar solvent, while methanol is a polar solvent.
- Due to the difference in polarity between the two components, the intermolecular forces between them are weaker than the forces between like molecules.
- This results in the molecules of benzene and methanol preferring to stay together rather than mixing uniformly in the solution.
- As a result, the observed vapor pressure of this solution is higher than what would be expected based on Raoult's law.
- This positive deviation occurs because the mixture has weaker intermolecular forces compared to the individual components.

In contrast, water-nitric acid, acetone-chloroform, and water-hydrochloric acid pairs do not exhibit a positive deviation from Raoult's law as the intermolecular interactions between the components are stronger, leading to a lower observed vapor pressure than predicted by Raoult's law.

Similar NEET Doubts

Which of the following solutions shows positive deviation from Raoults law?

The mixture which shows positive deviation from Raoult’s law is

Which of the following solutions is an example of negative deviation from Raoults law?

When acetone and chloroform are mixed together, hydrogen bonds are formed between them. Which of the following statements is correct about the solution made by mixing acetone and chloroform?

Which of the following are isomers a ethanol and ethoxy ethane be methanol and methoxymethane c propanoic acid and ethyl acetate d probainalde and acetone?

Top Courses for NEETView all

Biology Class 11

Daily Test for NEET Preparation

NEET Mock Test Series 2025

Topic-wise MCQ Tests for NEET

Physics Class 11

Top Courses for NEET

Top Courses for NEET

Suggested Free Tests

Related Content

About NEET

NEET Preparation Material

How to Prepare for NEET Exam?

NCERT Based Study Material

NEET Mock Tests

Other Popular Exams

Company