Answer:
[tex]74.64\ \text{g}[/tex]
Explanation:
Reactants
Magnesium = 24.3 g
Hydrogen chloride= x g
Products
Hydrogen gas = 2.04 g
Magnesium chloride = 96.9 g
As the mass of the reactions is conserved we have
Mass of reactants = Mass of products
[tex]24.3+x=2.04+96.9\\\Rightarrow x=2.04+96.9-24.3\\\Rightarrow x=74.64\ \text{g}[/tex]
Mass of hydrogen chloride is [tex]74.64\ \text{g}[/tex].