Question

The following reaction is an example of

${\mathrm{CH}}_4+2{\mathrm{O}}_2\to {\mathrm{CO}}_2+2{\mathrm{H}}_2\mathrm{O}+\mathrm{heat}+\mathrm{light}$

• A. Addition reaction
• B. Substitution reaction
• C. Combustion reaction
• D. Displacement reaction

Answer 1

The correct option is C

Combustion reaction

The explanation for the correct option:

(C):

• In this reaction, fuel is oxidized by reacting with oxygen, resulting in the release of energy (usually as light and heat) along with the formation of Carbon dioxide $\left({\mathrm{CO}}_2\right)$ and Water$\left({\mathrm{H}}_2\mathrm{O}\right)$.
• For example: When Methane $\left({\mathrm{CH}}_4\right)$ reacts with oxygen$\left({\mathrm{O}}_2\right)$, it results in the formation of carbon dioxide$\left({\mathrm{CO}}_2\right)$, water $\left({\mathrm{H}}_2\mathrm{O}\right)$ along with heat and light.

Chemical reaction:

• The chemical equation is as follows:-

${\mathrm{CH}}_4\left(\mathrm{g}\right)+2{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{CO}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)+\mathrm{heat}+\mathrm{light}$

The explanation for incorrect options:

(A) Addition reaction

• In addition reaction, hydrogen gets added to the unsaturated hydrocarbons and results in the formation of saturated hydrocarbons.
• It is one of the crucial organic reactions exhibited by organic compounds that comprise multiple bonds.

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(B) Substitution reaction

• A substitution reaction is a chemical reaction in which one kind of atom or group of atoms takes the place of another atom.
• Light and heat are not produced here.
• For example:

${\mathrm{CH}}_4+{\mathrm{Cl}}_2\stackrel{\mathrm{Sunlight}}{\to }{\mathrm{CH}}_3\mathrm{Cl}+\mathrm{HCl}$

(D) Displacement reaction:

• A displacement reaction occurs when one atom or a group of atoms is displaced by another atom.
• This reaction happens when a less reactive element gets displaced by a more reactive element.
• Example of displacement reaction:

$\mathrm{Fe}\left(\mathrm{s}\right)+{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)\to {\mathrm{FeSO}}_4\left(\mathrm{aq}\right)+\mathrm{Cu}\left(\mathrm{s}\right)$

• Light and heat are not produced here.

Hence, option (C) Combustion reaction is the correct option. In the given reaction, methane reacts with oxygen to form water and carbon dioxide along with heat and light. Therefore, this reaction is considered a combustion reaction.