a)
\(2C{H_2} = C{H_2} + {O_2}\xrightarrow{{xt,{t^^\circ }}}2C{H_3}CHO\)
\(C{H_3}CHO + B{{\text{r}}_2} + {H_2}O \to C{H_3}COOH + 2HB{\text{r}}\)
\(C{H_3}COOH + {C_2}{H_5}OH\overset {H{ & _2}S{O_4},{t^^\circ }} \leftrightarrows C{H_3}COO{C_2}{H_5} + {H_2}O\)
\(C{H_3}COO{C_2}{H_5}\xrightarrow{{LiAl{H_4},{t^^\circ }}}2C{H_3}C{H_2}OH\)
b)
\(C{H_3}C{H_2}COOH + B{r_2}\buildrel {{t^0}} \over \longrightarrow C{H_3}CHBrCOOH + HBr\)
\(C{H_3}CHBrCOOH + 2KOH\buildrel {{C_2}{H_5}OH,{\rm{ }}{t^0}} \over \longrightarrow C{H_2} = CHCOOK + KBr + 2{H_2}O\)
CH2=CHCOOK+HCl(l)→ CH2=CHCOOH+KCl
\(C{H_2} = CHCOOH + C{H_3}OH\buildrel {{t^0},{\rm{ }}{H_2}S{O_4}\left( \right)} \over \longrightarrow C{H_2} = CHCOOC{H_3} + {H_2}O\)
\(nC{H_2} = CHCOOC{H_3}\buildrel {{t^0},xt,p} \over \longrightarrow - {(C{H_2} - CH - COOC{H_3})_n} - \)
c) \(2C{H_2} = C{H_2} + {\rm{ }}{O_2}\buildrel {{t^0},xt} \over \longrightarrow {\rm{ }}2C{H_3} - CHO\)
\(C{H_3}COOH + C{H_2} = CH - OH\buildrel {{t^0},{\rm{ }}{H_2}S{O_4}\left( \right)} \over \longrightarrow C{H_3}COOCH = C{H_2} + {H_2}O\)
\(nC{H_3}COOCH = C{H_2}\buildrel {{t^0},xt,p} \over \longrightarrow - \left( {C{H_2} - CH - OCOC{H_3}} \right){ - _n}\).