What is the general equation for a combustion reaction?

A combustion reaction generally involves the reaction of a hydrocarbon (which can be represented as (CxHy)) with oxygen ((O_2)). The primary products of complete combustion of hydrocarbons are carbon dioxide ((CO_2)) and water ((H_2O)).

The answer representing this process accurately states that a hydrocarbon reacts with oxygen to produce carbon dioxide and water. This reflects the fundamental nature of combustion, where carbon in the hydrocarbon is oxidized to carbon dioxide, and hydrogen is oxidized to water.

In a balanced combustion reaction, for each molecule of the hydrocarbon combusted, sufficient oxygen is provided to ensure that all carbon and hydrogen atoms are accounted for in the form of (CO_2) and (H_2O) in the products. This explains why the correct choice illustrates that the complete reaction of a hydrocarbon with oxygen leads to these specific end products.