19 grams of zinc + HCl formed 6 liters of hydrogen. Find the fraction of the hydrogen yield.

1) The theoretical volume of hydrogen is determined by the reaction of interaction between zinc and hydrochloric acid:
Zn + 2HCl = ZnCl2 + H2, n (H2) = n (Zn) = 19 g: 65 g / mol = 0.29 mol;
Vtheor (H2) = 0.29 mol * 22.4 l / mol = 6.55 l;
2) From the condition, the practical volume of hydrogen produced is 6 liters. By definition of the reaction yield (the fraction of the substance yield) is the ratio of the practical result to the theoretically expected result:
η = 6 l / 6.55 l = 0.916 * 100% = 91.6%
Answer: the proportion of hydrogen yield in the reaction is 91.6%