Which type of reaction involves replacing a hydrogen on an alkane or aromatic with another atom?

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

Answer: (D)

Substitution reactions are about replacing a hydrogen atom on a saturated hydrocarbon (alkane) or on an aromatic ring with another atom or group. In alkanes, this often happens via radical mechanisms where a hydrogen is abstracted and a new atom (like chlorine or bromine) takes its place, giving a substituted alkane. In aromatic compounds, the hydrogen on the ring can be replaced by an electrophile through electrophilic aromatic substitution, still keeping the ring intact while a substituent takes the place of hydrogen.

That’s why this type of reaction fits the idea of swapping a hydrogen for another atom in both alkanes and aromatic systems. Combustion is rapid oxidation producing CO2 and H2O, not a replacement of H with another atom. Addition reactions add atoms to multiple bonds rather than replace an existing hydrogen. Ether is a class of compounds, not a reaction type, though certain reactions can form ethers.