Haloalkanes And Haloarenes

A bromoalkane '\(X\)' reacts with magnesium in dry ether to form compound '\(Y\)'. The reaction of '\(Y\)' with methanol followed by hydrolysis yield an alcohol having molecular formula, \(\mathrm{C}_4 \mathrm{H}_{10} \mathrm{O}\). The compound '\(X\)' is