Benzene And Alkyl Benzene Result Question 9
9. Among the following four aromatic compounds, which one will have the lowest melting point?
(2019 Main, 12 Jan I)
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Answer:
Correct Answer: 9. ( b )
Solution:
Melting point of a compound depends on size and force of attraction between the molecules. Compound (c) has largest size and also possess weak intermolecular association due to dipole - dipole interactions.
Compound (a) is a dicarboxylic acid and possess high melting point due to intermolecular hydrogen bonding.
As a result, it exist as associated molecule. Compound (d) is an alcohol and possess intermolecular H-bonding. No interactions are present in hydrocarbon (naphthalene) compound (b).
Hence, melting point is lowest for naphthalene ( $\simeq 80^{\circ} \mathrm{C}$ ), i.e. compound (b).
BETA
