\(O{H^ - } + CHC{l_5} \rightleftharpoons HOH + :CC{l_3} \to C{l^ - } + :CC{l_2}\)
${C_2}{H_5}OH\,\xrightarrow{{PB{r_2}}}X\,\xrightarrow{{KOH}}\,Y\,\xrightarrow[{(ii)\,{H_2}{O^ + }}]{{(i)\,{H_2}S{O_4}}}Z$