Which of the following compound can be used for the separation of ethanol from the mixture of ethanol and ethanal?
Correct answer: A. NaHSO3
- A. NaHSO3
- B. HCN
- C. NH2NH2
- D. Aldol
Explanation
The goal is to separate ethanol from ethanal. We need a reagent that reacts with one compound but not the other. So, the correct answer is A, NaHSO3.NaHSO3:Sodium Bisulfite reacts with aldehydes and certain ketones forming a white crystalline product of sodium bisulfite adduct. It is used to dintinguish between carbonyl and non-carbonyl compounds such as alcohols. Ethanal (CH₃CHO) is an aldehyde. It reacts with a saturated solution of sodium bisulfite (NaHSO₃) to form a white, crystalline addition product (the bisulfite adduct). Ethanol (CH₃CH₂OH) is an alcohol. It has no carbonyl group and does not react with NaHSO₃.Separation Process: When NaHSO₃ is added to the mixture, ethanal forms an insoluble crystalline solid, while ethanol remains in solution. The solid can be easily separated by filtration. The pure ethanal can later be regenerated from the adduct by treating it with a mild acid or base.
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About Aldehydes and Ketones
Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.
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