In the equation below, suppose 11 grams of zinc react with 12 grams of hydrogen chloride to form 16 grams of zinc chloride and an unknown amount of hydrogen gas.

Zn + 2HCl → ZnCl2 + H2

Based on the Law of Conservation of Mass, how many grams of hydrogen gas will form?

A:1 gram

B:7 grams

C:19 grams