Chlorobenzene would essentially be a benzene ring that is substituted with chlorine. Thus it would have 6 carbon atoms, in its molecular formula.
Unburned hydrocarbon on reacting with oxygen undergoes combustion reaction. However, the activation energy of this reaction is significantly high. When a catalyst like Pd is added to the reaction system, it provides active sites for the reaction to occur. It acts are a heterogeneous catalyst. It is pertinent of note that catalyst is refereed as heterogeneous, when it exist in different phase as compared to reactant and products. In present case, reactants and products are in gas phase, while catalyst is in solid phase. Due to availability of larger surface area at active site of Pd, activation energy of reaction decreases and decrease in activation energy favors higher reaction rates.
Answer:
See the image below for he circled and labeled functional groups.
*Keep in mind that all of the molecules technically contain alkanes.
