Phản ứng nào sau đây điều chế được CH₄ tinh khiết hơn ?

\(A{l_4}{C_3} + 12{H_2}O\xrightarrow{{}}4Al{(OH)_3} + 3C{H_4} \uparrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(1)\)

\({C_4}{H_{10}}\xrightarrow{{Crackinh}}{C_3}{H_6} \uparrow  + C{H_4} \uparrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2)\)

\(C{H_3}COON{a_r} + NaO{H_r}\xrightarrow{{CaO,\,\,{t^o}}}N{a_2}C{O_3} + C{H_4} \uparrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(3)\)

\(C{H_2}{(COONa)_2}_{\,\,r} + 2NaO{H_r}\xrightarrow{{CaO,\,\,{t^o}}}2N{a_2}C{O_3} + C{H_4} \uparrow \,\,\,\,\,\,(4)\)

\(C + 2{H_2}\xrightarrow{{{t^o}}}C{H_4} \uparrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(5)\)