`b)`

$2CH_4 \xrightarrow[\text{làm lạnh nhanh}]{1500^oC} C_2H_2 + 3H_2$

$CH \equiv CH + H_2 \xrightarrow[t^o]{Pd//PbCO_3} CH_2=CH_2$

`CH_2=CH_2 + Br_2 -> CH_2Br-CH_2Br`

$C_2H_4Br_2 + 2KOH \xrightarrow{rượu} C_2H_2 + 2KBr + 2H_2O$

$2CH \equiv CH \xrightarrow{t^o,p,xt} CH \equiv C - CH=CH_2 $

$CH \equiv C - CH = CH_2 + H_2 \xrightarrow[t^o]{Pd//PbCO_3} CH_2=CH-CH=CH_2$

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

`d)`

`CH_2=CH_2 + Cl_2 -> CH_2Cl-CH_2Cl`

$C_2H_4Cl_2 + 2KOH \xrightarrow{rượu} C_2H_2 + 2KCl + 2H_2O$

`CH \equiv CH + 2AgNO_3 + 2NH_3 -> AgC \equiv CAg + NH_4NO_3`

$c.$

$2CH_4 \xrightarrow[1500^oC]{lln}C_2H_2+3H_2$

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

$C_2H_4+Br_2 \to C_2H_4Br_2$

$C_2H_4Br_2+2KOH \xrightarrow{etanol}C_2H_2+2KBr+2H_2O$

$2C_2H_2 \xrightarrow{t^o,xt}C_4H_4$

$C_4H_4+H_2 \xrightarrow{t^o,Pd/PbCO_3}CH_2=CH-CH=CH_2$

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

$d)$

$C_2H_4+Cl_2 \to C_2H_4Cl_2$

$C_2H_4Cl_2+KOH \xrightarrow{etanol}C_2H_2+2KCl+2H_2O$

$C_2H_2+2AgNO_3+2NH_3 \to C_2Ag_2+2NH_4NO_3$

$C_2Ag_2+2HCl \to C_2H_2+2AgCl$

$3C_2H_2 \xrightarrow{\text{xt: bột C, }600^oC}C_6H_6$