in the equation mg+2hcl-->mgcl2+h2, what mass of the hcl is consumed by the reaction of 2.50 mol of magnesium

Answer 1

You need to learn to use the caps key when you do chemistry because co, Co and CO and not the same.
Mg + 2HCl ==> MgCl2 + H2
How many mols Mg? That's 2.50 mols in the problem.
Using the coefficients in the balanced equation, convert mols Mg to mol HCl. That will be 2.50 x (2 mol HCl/1 mol Mg) = 2.5 x 2/1 = ? mol HCl.
Now convert mols HCl to grams. g = moles x molar mass.

Answer 2

183