Question

Which pair of liquids on mixing is/are expected to show no net volume change and no heat effect ?

• A. acetone and ethanol
• B. chlorobenzene and bromo benzene
• C. chloroform and benzene
• D. n- butyl chloride and n-butyl bromide

Answer 1

Answer: (B), (D)

The correct options are
B chlorobenzene and bromo benzene
D n- butyl chloride and n-butyl bromide

No change in volume and no enthalpy of mixing means molecules of liquids should have similar size and same intermolecular forces.
Ethanol has hydrogen bonding where acetone doesn’t have any hydrogen bonding. So it doesn’t form ideal solutions.
Chloroform and benzene have different sizes and chloroform has polar intermolecular forces and benzene has non polar intermolecular forces. So they don’t form ideal solution.
Chloro benzene and bromo benzene are similar size and similar inter molecular forces. So they can form ideal solutions.
Same in the case of n- butyl chloride and n-butyl bromide.