Question

Complete the following reactions: (i) \(\ \text{CH}_3\text{OH} + \text{I}_2 + \text{NaOH} \xrightarrow{\Delta} \ ?\) (ii) \(\ \text{CH}_3\text{CH}_2\text{OH} \xrightarrow[\;523\,\text{K}\;]{\text{Al}_2\text{O}_3} \ ?\) (iii) \(\ \text{C}_2\text{H}_5\text{ONa} + \text{C}_2\text{H}_5\text{Br} \xrightarrow{\Delta} \ ?\)

Hint:

Iodoform test confirms presence of \(-\text{CH}_3\text{OH}\) or \(-\text{COCH}_3\) group. Williamson synthesis is the best method for preparing symmetrical and unsymmetrical ethers.

Answer 1

Step 1: Reaction (i) is the iodoform reaction. Alcohols containing the \(-\text{CH}_3\text{OH}\) group give yellow precipitate of iodoform (\(\text{CHI}_3\)).
Step 2: Reaction (ii) is acidic dehydration of alcohol. Alumina at high temperature converts ethanol into ethene.
Step 3: Reaction (iii) is Williamson ether synthesis, where an alkoxide reacts with an alkyl halide to form an ether.