ANS:D - an azeotrope may be formed during distillation.

For a binary mixture with low relative volatility:

• An azeotrope may be formed during distillation.

When a binary mixture has a low relative volatility, the vapor pressures of the components are similar, making it difficult to achieve effective separation by simple distillation. In such cases, an azeotrope, which is a mixture of two or more components that behaves as if it were a single substance with a fixed boiling point, may form during distillation. An azeotrope can be formed at a particular composition where the vapor and liquid phases have the same composition. This results in a constant boiling mixture with a specific boiling point that differs from the boiling points of the pure components. Azeotropic distillation techniques, such as extractive distillation or heterogeneous azeotropic distillation, can be employed to break the azeotrope and separate the components effectively. Steam distillation, molecular distillation, or high-pressure distillation may not be effective for separating components with low relative volatility because these techniques are typically used for systems with high relative volatilities or to handle specific properties like heat sensitivity or vacuum conditions. Therefore, the formation of an azeotrope during distillation is a more relevant option for binary mixtures with low relative volatility.