MCQ Detailed View

Clemmensen reduction is a chemical reaction used to reduce carbonyl groups of aldehydes and ketones to alkanes. The reagents used are zinc amalgam (Zn(Hg)) and concentrated hydrochloric acid (HCl). This reaction works best with ketones or aldehydes that are stable under strongly acidic conditions.

Acetone is a simple ketone with the formula CH₃–CO–CH₃. When acetone undergoes Clemmensen reduction, the carbonyl group (C=O) is completely reduced, and the oxygen is removed. The double bond between carbon and oxygen is replaced by two hydrogen atoms, converting the carbonyl carbon into a –CH₂– group. This results in the formation of propane (CH₃–CH₂–CH₃), a saturated hydrocarbon (alkane).

The reaction can be summarized as:
CH₃–CO–CH₃ + 4[H] → CH₃–CH₂–CH₃ + H₂O

Ethanol (CH₃CH₂OH) and propanol (CH₃CH₂CH₂OH) are alcohols, which are not produced in this reaction. Ethanal (CH₃CHO) is an aldehyde, also not the product of ketone reduction by Clemmensen conditions. The only correct product is propane.

Clemmensen reduction is especially useful in organic synthesis when converting aryl or aliphatic ketones to alkanes. It is commonly applied to synthesize hydrocarbons from ketones that are part of complex molecules. This reaction is not suitable for compounds that are sensitive to acid, as it uses strongly acidic conditions.

This MCQ helps reinforce the understanding of named organic reactions, especially reductions involving ketones and aldehydes, and is important for exams involving reaction mechanisms in organic chemistry.