To determine which of the given options represents an elimination reaction, let's first briefly discuss what an elimination reaction is. An elimination reaction is a chemical reaction where two atoms or groups are removed from a molecule, resulting in the formation of a double bond or a new molecule, typically an alkene or alkyne.
Let's analyze each provided option:
Option A:
[tex]\[ \text{CH}_3 \text{COONa} + \text{NaOH} \xrightarrow[\text{heat/light}]{\text{CaO}} \text{CH}_4 + \text{Na}_2 \text{CO}_3 \][/tex]
This is a decarboxylation reaction, where a carboxyl group is removed from a carboxylate. This reaction does not fit the typical characteristics of an elimination reaction.
Option B:
[tex]\[ \text{CH}_4 + \text{Cl}_2 \xrightarrow[\text{sun}]{\text{light}} \text{CH}_3 \text{Cl} + \text{HCl} \][/tex]
This is a substitution reaction, specifically a halogenation where a hydrogen atom is replaced by a chlorine atom. This is not an elimination reaction.
Option C:
[Option C has been left blank by the user for now.]
Option D:
[tex]\[ \text{CH}_3 \text{-CH}_2 \text{-CH}_3 \xrightarrow{460^{\circ} \text{C }} \text{H}_2 \text{C}=\text{CH}_2 + \text{CH}_4 \][/tex]
This reaction is an example of an elimination reaction (in this case, a dehydrohalogenation reaction), where two hydrogen atoms are removed from propane resulting in the formation of ethene and methane. This fits the definition of an elimination reaction as a single molecule (propane) loses atoms to form a double bond (ethane) and another product (methane).
Hence, the correct answer is:
D. [tex]\(\text{CH}_3 \text{-CH}_2 \text{-CH}_3 \xrightarrow{460^{\circ} \text{C }} \text{H}_2 \text{C}=\text{CH}_2 + \text{CH}_4 \)[/tex]
