Question

given a mixture of pentane and pentane - 1,2,3 - triol, which of the following compounds can be used to dissolve the pentane (so that it can be separated from the pentane - 1,2,3 - triol)?

i. cyclohexane
ii. water
iii. phenol
iv. ethanol

Explanation:

Step1: Recall solubility principle

Like - dissolves - like. Non - polar substances dissolve in non - polar solvents, and polar substances dissolve in polar solvents. Pentane is a non - polar hydrocarbon, and pentane - 1,2,3 - triol is a polar compound due to the presence of multiple hydroxyl groups.

Step2: Analyze each option

Option I: Cyclohexane

Cyclohexane is a non - polar hydrocarbon. It will dissolve pentane (a non - polar compound) according to the like - dissolves - like principle.

Option II: Water

Water is a highly polar compound. It will dissolve the polar pentane - 1,2,3 - triol (due to hydrogen bonding with the hydroxyl groups) but not the non - polar pentane.

Option III: Phenol

Phenol has a polar hydroxyl group and a non - polar aromatic ring. However, its polar nature is more dominant due to the hydroxyl group, and it will have a greater affinity for the polar pentane - 1,2,3 - triol rather than non - polar pentane.

Option IV: Ethanol

Ethanol is a polar compound due to the hydroxyl group. It will dissolve the polar pentane - 1,2,3 - triol through hydrogen bonding and is not an ideal solvent for non - polar pentane.

Answer:

I. cyclohexane