Chemistry - Liquid Solution Question with Solution | TestHub
Which of the following binary solution exhibits higher vapor pressure than the vapour pressure of its pure components at same temprecure?
Options:
Answer:
Solution:
A solution exhibits a higher vapour pressure than the vapour pressure of its pure components if it shows a positive deviation from Raoult's law.
In a mixture of ethanol and acetone, the pure ethanol molecules are strongly hydrogen-bonded. When acetone is added, its molecules get between the ethanol molecules and break some of these hydrogen bonds.
This weakens the intermolecular attractive forces, meaning the A-B interactions are weaker than the A-A and B-B interactions. As a result, the escaping tendency of the molecules increases, leading to a higher vapour pressure (positive deviation).
Benzene and toluene form an ideal solution.
Phenol and aniline show a negative deviation due to strong intermolecular hydrogen bonding between them.
Chloroform and acetone also show a negative deviation due to hydrogen bonding between the hydrogen of chloroform and the oxygen of acetone.
Answer: ethanol + acetone
