$CH_3COONa+ NaOH \buildrel{{CaO, t^o}}\over\longrightarrow CH_4+ Na_2CO_3$ 
$CH_4+ Cl_2 \buildrel{{as}}\over\longrightarrow CH_3Cl+ HCl$ 
$CH_3Cl+ Cl_2 \buildrel{{as}}\over\longrightarrow CH_2Cl_2+ HCl$
$CH_2Cl_2+ Cl_2 \buildrel{{as}}\over\longrightarrow CHCl_3+ HCl$ 
$CHCl_3+ Cl_2 \buildrel{{as}}\over\longrightarrow CCl_4+ HCl$