$H_2C = CH - CH_2 - I \xrightarrow[CC{{l}_{4}}]{HI(excess)}$
${H_3}C - C \equiv CH\,\xrightarrow[{HgS{O_4}}]{{{H_2}O,\,{H_2}S{O_4}}}\,\mathop {intermediate}\limits_{(A)} \,$$ \to \,\mathop {\Pr oduct}\limits_{(B)} $
${C_2}{H_2}\xrightarrow[{HgS{O_4}/{H_2}S{O_4},60{\,^o}C}]{{{H_2}O}}X \rightleftharpoons C{H_3}CHO$
ઉપર ની પ્રકિયા માં નીપજ $(A)$ શું હશે ?