Write the equation for controlled oxidation of methane to form methyl alcohol.

Write the equation for controlled oxidation of methane to form formaldehyde.

Write the equation for controlled oxidation of methane to form formic acid.

Write balanced chemical equation when a mixture of methane and oxygen (in the volume ratio $9:1$) is passed through a copper tube at $200°\mathrm{C}$ and $100 \mathrm{atm}$.

Write balanced chemical equation when a mixture of methane and oxygen is heated in the presence of a metallic oxide which acts as a catalyst.

Write balanced chemical equation when a mixture of methane and air is heated at $473 \mathrm{K}$ and $130 \mathrm{atm}$.