`a,`

`PTHH: nCH_2=CH_2` $\xrightarrow{t^o,xt,p}(\kern-6pt- CH_2-CH_2 -\kern-6pt)_n$

`C_2H_4+H_2O` $\xrightarrow{t^o,H_2SO_4}$ `C_2H_5OH`

`C_2H_5OH+O_2` $\xrightarrow[28^o-35^oC]{\text{men giấm}}$ `CH_3COOH+H_2O`

`CH_3COOH+C_2H_5OH` $\buildrel{{t^o,H_2SO_4}}\over\rightleftharpoons$ `CH_3COOC_2H_5+H_2O`

`b,`

`CaC_2+H_2O->C_2H_2+Ca(OH)_2`

`C_2H_2+H_2` $\xrightarrow{t^o,Pd/PbCO_3}$ `C_2H_4`

`C_2H_4+H_2O` $\xrightarrow{t^o,H_2SO_4}$ `C_2H_5OH`

`C_2H_5OH+O_2` $\xrightarrow[28^o-35^oC]{\text{men giấm}}$ `CH_3COOH+H_2O`