For the problem(s) that follow, consider the reaction in which magnesium reacts with an HCl solution .
Mg(s) + 2HCl(aq) → MgCl₂(aq) + H2(g)
-If 2.00 g of Mg reacts completely with 50.0 mL of HCl solution, what is the molarity of the HCl solution?
A)1.65 M
B)80.0 M
C)8.00 M
D)0.823 M
E)3.29 M

Question

Quizplus · Accepted Answer

To find the molarity of the HCl solution, first calculate the moles of Mg: 2.00 g Mg * (1 mol Mg / 24.31 g Mg) = 0.0823 mol Mg. The balanced equation shows that 1 mol Mg reacts with 2 mol HCl, so 0.0823 mol Mg reacts with 0.1646 mol HCl. Molarity (M) is moles of solute per liter of solution: 0.1646 mol HCl / 0.050 L = 3.29 M.

For the Problem(s) That Follow, Consider the Reaction in Which