Some oxidation reactions of methane are given below. Which of them is/are controlled oxidation reactions?

1. ${\mathrm{CH}}_{4}\left(\mathrm{g}\right)+2{\mathrm{O}}_{2}\left(\mathrm{g}\right)\to {\mathrm{CO}}_{2}\left(\mathrm{g}\right)+2{\mathrm{H}}_{2}\mathrm{O}\left(\mathrm{l}\right)$

2. ${\mathrm{CH}}_{4}\left(\mathrm{g}\right)+{\mathrm{O}}_{2}\left(\mathrm{g}\right)\to \mathrm{Cl}\left(\mathrm{s}\right)+2{\mathrm{H}}_{2}\mathrm{O}\left(\mathrm{l}\right)$

3. ${\mathrm{CH}}_{4}\left(\mathrm{g}\right)+{\mathrm{O}}_{2}\left(\mathrm{g}\right)\stackrel{{\mathrm{Mg}}_{2}{\mathrm{O}}_{3}}{\to }\mathrm{HCHO}+{\mathrm{H}}_{2}\mathrm{O}$

4.

(3, 4)
Alkanes on heating with a regulated supply of dioxygen or air at high pressure and in the presence of suitable catalysts give a variety of oxidation products.
${\mathrm{CH}}_{4}+{\mathrm{O}}_{2}\underset{∆}{\overset{{\mathrm{Mo}}_{2}{\mathrm{O}}_{3}}{\to }}\mathrm{HCHO}+{\mathrm{H}}_{2}\mathrm{O}$