Identify the product \('X'\) in the following reaction:

The correct answer is option 4.

When alkyl halide is heated with alc. sodium or potassium alkoxide gives corresponding ethers. Simple ethers can be easily prepared by this method.

But for preparation of mixed ether a proper choice of reactant is necessary. Primary alkyl halide is more susceptible to \(S_N2\) reaction. Therefore, best yield of ether obtained when alkyl halide is primary and alkoxide is tertiary.

Example: tert-butyl ether is prepared by heating ethyl bromide with sodium tert-butoxide.

But when alkyl halide is secondary or tertiary the nucleophilic attack of alkoxide ion on \(\alpha \)−carbon atom becomes difficult due to crowding effect. Since alkoxide is a stronger base and attacking \(beta \)− hydrogen is easier. Therefore, \(beta \)− elimination dominates.

Therefore, the correct answer is option 4.