Question

1. choose the best answer. what is likely a reactant in a combustion reaction? light li⁺ c₂h₄ heat 2) choose the best answer. what is always produced during a combustion reaction? water metals hydrogen gas salts

Explanation:

1. Combustion reactions involve a fuel reacting with an oxidizer (usually oxygen) to produce oxides, heat, and light. Among the options, $\text{C}_2\text{H}_4$ (ethylene) is a common fuel that acts as a reactant in combustion.
2. Complete combustion of hydrocarbon fuels (the most common type of combustion) always produces water ($\text{H}_2\text{O}$) along with carbon dioxide; even for non-hydrocarbon combustible substances, many will form water if hydrogen is present, and it is a consistent product relative to the other options.

Answer:

1. $\text{C}_2\text{H}_4$
2. water