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.
Atoms (Sodium and Fluorine)
Answer:
Chlorine is the element located in period 3, group 17 of the periodic table.
Explanation: