hexane and ethanol are miscible liquids. ethanol is soluble in water while hexane is insoluble. explain how water can be used in the separation of hexane and ethanol.
The Correct Answer and Explanation is:
Water can be used to separate hexane and ethanol due to the differences in their solubility properties and the principle of liquid-liquid extraction. Hexane and ethanol are miscible in one another, meaning they mix completely to form a single homogeneous solution. However, water can act as a selective solvent due to its unique interaction with ethanol and its lack of solubility in hexane.
Ethanol is highly soluble in water because both are polar substances, and the hydrogen bonding between water molecules and ethanol molecules is strong. On the other hand, hexane is a nonpolar substance and does not mix well with water. This is due to the lack of intermolecular forces between hexane molecules and water molecules.
When water is added to a mixture of hexane and ethanol, the ethanol dissolves in the water because of the strong hydrogen bonds formed between ethanol and water molecules. As a result, ethanol will partition into the aqueous phase (water), leaving hexane behind in the organic phase. Since hexane is insoluble in water, it will remain in the nonpolar organic phase.
To separate the two liquids, a separating funnel can be used. After adding water to the hexane-ethanol mixture, the system is allowed to stand so that the two phases—aqueous (water with ethanol) and organic (hexane)—separate due to their differing densities. The aqueous phase, which contains ethanol, can be drained off, leaving hexane in the organic layer.
This method exploits the principle of solubility differences and phase separation based on polarity. By using water, a selective solvent for ethanol, it is possible to separate ethanol from hexane efficiently.
