How many moles of hydrogen are consumed when 40.0 L of hydrogen chloride gas are produced in the following equation?

Question

H2(g) + Cl2(g) 2 HCl(g)

Answer 1

1. You need to add an arrow to your equation. Equations without arrows to separate the products from the reactants are useless.

2. Here is an example problem I've posted of a stoichiometry problem (which this is). Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html