Ethers MCQ Quiz in मराठी - Objective Question with Answer for Ethers - मोफत PDF डाउनलोड करा

Correct answer: 2) 

Concept:

• Ethers are readily attacked by concentrated HI and decomposed into RI.
• The ethereal linkage is broken and the products formed depend on the temperature of the reaction.
• With cold HI a mixture of alky iodide then alcohol is formed. In the case of mixed ethers, the halogen atom attaches to a smaller and less complex alkyl group. 
• 
• When heated with excess HI, only alkyl iodides are formed. 

Explanation:

• Ethers react with hydroiodic acids to form an alcohol/phenol and corresponding haloalkane.
• However, with hot halogen acids, only the haloalkanes are formed.
• This is because as soon as the alcohol is formed, it will react with hydroiodic acid and get converted to the corresponding halo alkane and water.
• When Phenyl alkyl ether reacts with HI to give phenol and alkyl iodide and not iodobenzene and alcohol because I⁻ ion prefers to combine with the smaller group in order to minimize steric hindrance.
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Conclusion:

• Thus, option 2 is the correct answer.

Concept:

In presence of r₂/EtOH, the reactant containing double bond undergoes electrophilic addition reaction via the formation of bromonium ion. On further attack of \(-\ddot{\underset{\scriptscriptstyle\centerdot\centerdot}{O}}\) Me on bromonium ion gives the addition product.