most important named reaction.

The reaction in which carbonyl group (C=O) is reduced into (-CH2-) group on reacting with a mixture of zinc and hydrochloric acid is called Clemmensen,s Reduction.

General reaction:-

Reaction of aliphatic aldehyde and ketones-

Reaction of aromatic aldehyde and ketones-

Question:- Why did a mixture of Zn+HCl is used for reduction ?
Answer:- Zn reaction reacts with HCl to produce H₂gas which reduces carbonyl (C=O) to alkane (-CH₂-).

Question:- Why does amalgam of Zinc (Zn/Hg) use in spite of only Zn ?
Answer:- Zn reacts with HCl to produce H₂ very fast that move out fast from reaction mixture and carbonyl compound has very little time to react and most of hydrogen moves out of reaction mixture without reacting whereas in form of amalgam, Zn reacts slowly to produce hydrogen slowly, which can react with carbonyl compound. because only those Zn atoms reacts with HCl which are present on the surface of amalgam .

Amalgam: The solution of metal in mercury is called amalgam. Metal dissolve in mercury like salt dissolve in water.

The reaction in which the carbonyl compound (having no alpha hydrogen) is treated with base (NaOH or KOH) to produce alcohol and Carboxylate ion is called Cannizzaro’s reaction.

The cannizzro,s reaction is given by the aldehydes which has no alpha hydrogen.
The aldehyde oxidizes to carboxylate ion and reduced to alcohol.
Cannizzaro’s reaction is disproportionation reaction.
The reaction in which same molecule oxidizes and reduced simultaneously is called disproportionation reaction..

Question:- Which compounds gives Cannizzaro’s reaction out of the following compounds and why?

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