Question

Which of the following options gives ethyl benzene with phenyl methyl ketone?
A. \[Zn - Hg + HCl\]
B. \[LiAl{H_4}\]
C. \[KMn{O_4}\]
D. None of the above

Answer 1

Hint: Phenyl Methyl ketone (Acetophenone) is the organic compound with the formula \[{C_6}{H_5}CC{H_3}\]. It is known as the simplest aromatic ketone. It is a colourless and viscous liquid and is useful in making resins and fragrances as a precursor. The ketone group of the Phenyl methyl ketone compound is being reduced in this reaction.

Complete Step by Step Solution:
For reducing aldehydes or ketones, zinc amalgam along with HCl is used. This reaction which reduces ketones or aldehydes is also known as Clemmensen's reduction reaction. It is named after the famous Danish chemist, Erik Christian Clemmensen. The reaction is carried out below:

Image: Chemical Reaction
Thus, the correct answer to this question will be, option (A).

Additional Information:
Alkane from alkenyl chloride (halide) can be prepared from any organic compound which is transformed into alkenyl halide. This reaction is widely used to convert the carbonyl group into a methyl group. Preparation of polycyclic aromatics and aromatics containing the unbranched sides of the hydrocarbon chain. The reaction helps to reduce the aliphatic and the mixed aliphatic-aromatic carbonyl compounds. The Clemmensen reduction is most widely used to transform acyl benzene (from acylation by Friedel-Crafts) to alkylbenzene.

Note: The mechanism of the Clemmensen reduction reaction is not well known. Still, there are two proposals for its mechanism:
1) Carbanionic Mechanism: In the Carbanionic mechanism, zinc attacks directly the protonated carbon.
2) Carbenoid Mechanism: It's a radical process that reduces the happenings on the metal surface of zinc. The reaction of the carbenoid mechanism always takes place at the surface of the zinc catalyst.