Chemistry - ALCOHOL & ETHER Question with Solution | TestHub

Question Explanation: Predict the products when HI (excess) reacts with an aryl alkyl ether.

Concept: This question is based on the acidic cleavage of ethers through an S${}_N$1/S${}_N$2 pathway, depending on the alkyl group and substituents. Solution: 1. Cleavage of aryl–alkyl ether: – The Ar–O bond does not break (it is too strong). – The O–CH₃ bond cleaves, giving phenol + CH₃I. 2. Cleavage of secondary alkyl ether:

– HI protonates the ether, then I⁻ attacks the carbon bearing –CN. This carbon is highly activated by the –I effect of the –CN group, favoring an S${}_N$2 attack. – Product formed: Ar–CH(I)–CN (iodo–nitrile).