As a result of chemical reactions 2HCl + Mg = MgCl2 + H2 ↑ – hydrogen was formed with a chemical amount of 0.450 mol

As a result of chemical reactions 2HCl + Mg = MgCl2 + H2 ↑ – hydrogen was formed with a chemical amount of 0.450 mol, determine the chemical amount of HCl that reacted.

Given:
n (H2) = 0.450 mol

To find:
n (HCl) -?

Decision:
1) Write the equation of a chemical reaction:
2HCl + Mg => MgCl2 + H2 ↑;
2) Find the amount of HCl substance (taking into account the coefficients in the reaction equation):
n (HCl) = n (H2) * 2 = 0.450 * 2 = 0.9 mol.

Answer: The amount of HCl substance is 0.9 mol.