Answer:
is a combustion reaction
Explanation:
The reaction is a combustion since you have a hydrocarbon reacting with oxygen to form water and carbon dioxide.
The balanced equation is: 
If this helped, a brainliest answer would be greatly appreciated!
According to Dalton's Atomic Theory, the <em>Law of Definite Proportion is applied when a compound is always made up by a fixed fraction of its individual elements.</em> This is manifested by the balancing of the reaction.
The reaction for this problem is:
H₂ + Cl₂ → 2 HCl
1 mol of H₂ is needed for every 1 mole of Cl₂. Assuming these are ideal gases, the moles is equal to the volume. So, if equal volumes of the reactants are available, they will produce twice the given volumes of HCl.