Answer:
Option A. Substitution
Explanation:
To know which option is correct, let us define each option. This is illustrated below:
A substitution reaction is a reaction in which an halogen replaces hydrogen in a hydrocarbon to produce alkyl halide and the corresponding acid. For example:
RH + X₂ –> RX + HX
NOTE:
R => is an alkyl group
X => is an halogen (F₂, Cl₂, Br₂ or I₂)
Addition reaction is a reaction in which two reactants combined to form a new compound without any loss of the reactants. This reaction is peculiar to only unsaturated hydrocarbon. For example:
CₓHᵧ + A₂ —> ACₓHᵧA
NOTE:
CₓHᵧ => unsaturated hydrocarbon (alkene, alkyne)
A₂ => halogen (F₂, Cl₂, Br₂ or I₂) or HBr, HCl etc
Esterification is a reaction involving carbonxylic and alcohol to produce ester and water. For example:
RCOOH + HOR —> RCOOR + H₂O
NOTE:
R => is an alkyl group
Polymerization is a process of reacting smaller molecules called monomers to form a larger molecule called polymer.
With the information provided above, we can see that the reaction:
CH₄ + Br₂ —> CH₃Br + HBr
Is a substitution reaction since Br replaces H in CH₄ to produce CH₃Br and the corresponding acid i.e HBr