Question

Pick up the correct statement.

• A. The boiling points of alkyl halides are more than those of the corresponding alkanes
• B. In water, the solubility of ${CH}_{3}OH>C_2{H}_{5}OH>C_6{H}_{5}OH$
• C. $C_6{H}_5{NH}_2$ is a weaker base than ${NH}_3$
• D. All the above statements are correct

Answer 1

Answer: (D)

All the above statements are correct

(A) The boiling points of alkyl halides are considerably higher than those of the corresponding alkanes. The main reason for this is the dipole moment of alkyl halides, which leads to attractive dipole-dipole interactions in liquid alkyl halides. Furthermore, the higher molar mass and the stronger London forces (Cl, Br and I) lead to higher boiling points.

(B)The solubility of lower alcohols in water is due to their ability to form new hydrogen bonds with water molecules. Since $C_6{H}_{5}OH$ has larger alkyl part, which interrupts in hydrogen bond formation, therefore solubility decreases with an increase in molecular mass. The order of solubility in water is $C{H}_{3}OH>C_2{H}_{5}OH>C_6{H}_{5}OH$.

(C) $C_6{H}_{5}N{H}_2$ is a weaker base than $N{H}_3$ because in aniline the lone pair of $N$ is in delocalization with benzene ring and not freely available to donate while it is free in $N{H}_3$.