Question

Assertion (A) The melting points and boiling points of aliphatic acids are usually higher than those of aromatic acids of comparable molecular masses.
Reason (R) The planar benzene ring in the aromatic acids can fit more closely in the crystal lattice than zig-zag structure of aliphatic acids.

• A. Both $A$ and $R$ are correct; and $R$ is the correct explanation of $A$.
• B. Both $A$ and $R$ are correct; but $R$ is not the correct explanation of $A$.
• C. $A$ is correct ; but $R$ is incorrect.
• D. $R$ is correct ; but $A$ is incorrect.

Answer 1

Answer: (D)

The melting points and boiling points of aromatic acids are usually higher than those of aliphatic acids of comparable molecular masses. This is due to the planar benzene ring in the aromatic acids which can fit more closely in the crystal lattice than zig-zag structure of aliphatic acids.