Chemistry gas question?

Question

When a volume of H2 reacts with an equal volume of Cl2 at the same temp and pressure, what volume of the product having the formula HCl is formed?

Answer 1

H2 + Cl2 → 2HCl

The volume of HCl gas formed will be the volume of the individual reactants combined.

Answer 2

A volume equal to the sum of the volumes of the original hydrogen and  chlorine.

Avogadro's Law says that one molecule of any gas occupies the same volume at the same temperature and pressure. Effectively, the reaction starts with two molecules (one H2 & one Cl2) and ends with two molecules (two HCl). The total volume will be the same.

Answer 3

Avogado's Law -- k = V/n -- tells us that the volumes of gases at the same pressure and temperature are in the same ratio as the moles of gases.  In other words, we can use the ratio of the coefficients in the balanced chemical equation to give us the ratios of the volumes of the gases.

H2(g) + Cl2(g) -->  2HCl(g)

1L of H2 reacts with 1L of Cl2 and produces 2L of HCl.

========= Follow up =========

Be careful.  Kumorifox's explanation sounds like he is saying that the volume of the HCl is 2L because the sum of the volumes of H2 and Cl2 is 2L.  That is not the case.

Consider the combustion of hydrogen in oxygen.

2H2(g) + O2(g) --> 2H2O(g)

2L ......... 1L ..............??? L

According to Kumorifox's logic, we should get 3L of water vapor.  We don't.  We get 2L of water vapor.  

2H2(g) + O2(g) --> 2H2O(g)

2L ......... 1L ................2L

The volumes of the gases are in the same ratio as the moles, which are given by the coefficients in the balanced equation.

Notice that Engineer01 is saying the same thing that I think Kumorifox is saying.  I hate to say it, but they are both wrong.