CUET · CHEMISTRY · PYQ PAPER 2025
Read the passage carefully and answer the questions
The carbonyl group of aldehydes and ketones is highly polar. The positively charged carbon is readily attacked by electron-rich nucleophile and the negatively charged oxygen atom is attacked by an electro-deficient electrophile. Aldehydes and ketones undergo nucleophilic addition reactions in the presence of acid or a base. The mechanism involves attack of a nucleophile on the electron deficient carbonyl carbon to form a tetrahedral intermediate. A new bond is formed between the carbon and oxygen. Protonation of the anion furnished by the reaction medium yields a neutral addition product. The addition product is same whether the reaction is catalyzed by acid or a base. For example in the presence of base aldehydes and ketones react with hydrogen cyanide to form cyanohydrin.
Which of the following reactions is not a nucleophilic addition reaction of aldehydes and ketones?
- A Addition of water
- B Addition of sodium Hydrogen Sulphite
- C Addition of alcohol
- D Addition of sodium borohydride
Answer & Solution
Correct Answer
(C) Addition of alcohol
Step-by-step Solution
Detailed explanation
The formation of acetals from aldehydes/ketones and alcohols is an overall reaction that involves an initial nucleophilic addition (to form a hemiacetal) followed by a dehydration step and a second nucleophilic attack/substitution. This process results in the elimination of a…
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