Question

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

• A. $C{H}_4\left(g\right)+2O_2\left(g\right)\to C{O}_2\left(g\right)+2H_{2}O\left(l\right)$
• B. $C{H}_4\left(g\right)+O_2\left(g\right)\to C\left(s\right)+2H_{2}O\left(l\right)$
• C. $C{H}_4\left(g\right)+O_2\left(g\right)\stackrel{M{o}_2{O}_3}{⟶}HCHO+H_{2}O$
• D. $2C{H}_4\left(g\right)+O_2\left(g\right)\stackrel{Cu/523/100atm}{⟶}2C{H}_{3}OH$

Answer 1

Answer: (C), (D)

The correct options are
C $C{H}_4\left(g\right)+O_2\left(g\right)\stackrel{M{o}_2{O}_3}{⟶}HCHO+H_{2}O$
D $2C{H}_4\left(g\right)+O_2\left(g\right)\stackrel{Cu/523/100atm}{⟶}2C{H}_{3}OH$

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. This process is called controlled oxidation.
In (c) and (d), methane is heated with a regulated supply of $O_2$/air at high pressure, in the presence of a $M{o}_2{O}_3$ and $Cu$ to give formaldehyde and methanol.
$2C{H}_4+O_2\stackrel{Cu//523K//100atm}{⟶}2C{H}_{3}OHC{H}_4+O_2\underset{\Delta }{\overset{M{o}_2{O}_3}{\to }}HCHO+H_{2}O$(a) is combustion reaction of methane.
(b) is the incomplete combustion reaction of methane.