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

Câu hỏi :

Phản ứng nào sau đây điều chế được CH₄ tinh khiết hơn ?\(\begin{array}{l} A{l_4}{C_3} + 12{H_2}O \to 4Al{(OH)_3} + 3C{H_4} \uparrow {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} (1)\\ {C_4}{H_{10}} \to {C_3}{H_6} \uparrow + C{H_4} \uparrow {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} (2)\\ C{H_3}COON{a_r} + NaO{H_r} \to N{a_2}C{O_3} + C{H_4} \uparrow {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} (3)\\ C{H_2}{(COONa)_2}_{\,\,r} + 2NaO{H_r} \to 2N{a_2}C{O_3} + C{H_4} \uparrow {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} (4)\\ C + 2{H_2} \to C{H_4} \uparrow {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} (5) \end{array}\)