Mixture of chloroform and acetone forms a solution with negative deviation from Raoult's law due to :
- Stronger intermolecular forces between chloroform molecules than those between chloroform and acetone molecules
- Formation of hydrogen bonding between acetone and chloroform
- Repulsive forces
- Increase in escaping tendency of molecules of each component
Answer
(2) Formation of hydrogen bonding between acetone and chloroform
Solution
As per NCERT, chloroform molecule is able to form hydrogen bond with acetone molecule:
Cl3C-H O=C(CH3)2
⇒ A–B interactions become stronger than A–A and B–B interactions
⇒ escaping tendency of molecules decreases ⇒ vapour pressure is lower than that predicted by Raoult's law
∴ the solution shows negative deviation due to hydrogen bonding between acetone and chloroform.
Answer: (2)