Ethanal reacts with HCN to form cyanohydrin. This is an example of:
Correct answer: A. Nucleophilic addition
- A. Nucleophilic addition
- B. Electrophilic addition
- C. Electrophilic substitution
- D. Nucleophilic substitution
Explanation
It is an example of nucleophilic addition. The CN- ion has a negative charge and it is attracted to a positive charge so CN- is a nucleophile. CN- forms a sigma bond with the electron-deficient species i.e. C of ethanol.
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About Nucleophilic Addition Reactions
Nucleophilic addition occurs at the polar carbonyl group of aldehydes and ketones, where a nucleophile attacks the electron-deficient carbon atom. Reactions with hydrogen cyanide, sodium bisulfite, alcohols and Grignard reagents are explained through tetrahedral intermediates, acid or base catalysis, and the different reactivity of aldehydes and ketones.
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