Question

Which has Part A the higher boiling point: 1-bromopentane or 1-bromohexane? 1-bromopentane 1-bromohexane Request Answer Submit Part B the higher boiling point: pentyl chloride or isopentyl chloride? pentyl chloride isopentyl chloride Submit Request Answer Part C the greater solubility in water: 1-pentanol or 1-hexanol? 1-pentanol

Answer 1

​​​Part A:-

1-bromohexane has higher boiling point than 1-bromopentane.

The boiling point of bromo-alkanes arises with increase in molecular mass or increase in size of alkyl group. This is because increase in size of alkyl group will increase the magnitude of vander Waal forces between the alkyl group or chain.

Part B:-

Pentyl chloride has higher boiling point than iso-pentyl chloride.

This is because boiling point decreases with branching of alkyl chain.

Part C:-

1-pentanol has higher solubility in water than 1-hexanol.

The solubility of alcohols in water decreases with increase in molecular mass, I.e., with increase in the size of the alkyl chain. 1-hexanol has higher molecular mass than 1-pentanol, and thus, its solubility in water is less than 1-pentanol. The alkyl group are hydrophobic and are insoluble in water. In lower alcohols, the alkyl group is small and the -OH group of the alcohol is effective in making the molecule water soluble. As the size of alkyl group increases in higher alcohols , the hydrophobic nature of alkyl group dominates over the hydrophilic nature of -OH group. Consequently, the solubility decreases. That is why, the solubility of alcohols decreases with increase in molecular mass.