An optically active alkyl halide \( \mathrm{C_4H_9Br} \) \([A]\) reacts with hot \( \mathrm{KOH} \) dissolved in ethanol and forms alkene \([B]\) as major product which reacts with bromine to give dibromide \([C]\). The compound \([C]\) is converted into a gas \([D]\) upon reacting with alcoholic \( \mathrm{NaNH_2} \). During hydration \( 18 \) gram of water is added to \( 1 \) mole of gas \([D]\) on warming with mercuric sulphate and dilute acid at \( 333 \, \mathrm{K} \) to form compound \([E]\). The IUPAC name of compound \([E]\) is :
