Answer:
Boil the water and stir in potassium nitrate. If it doesn't all dissolve, you can cook it on the stove or microwave it until the water boils again. Remove the solution from heat, but let it cool slowly for the best crystal formation.
0.075 L * 1.0 M = 0.075 mol HCl
H2 is half of HCl by the coefficients divide 0.075 by 2 and get 0.0375 mol H2 gas
**Visible confusion** no problem
