Chemistry Homework

Question

A 25.0 mL solution of HNO₃ is neutralized with 13.7 mL of 0.125 M Sr(OH)₂. What is the concentration of the original HNO₃ solution

Answer 1

We know to neutralize solutions, the amount of OH- ions has to equal the amount of H+ ions. Let's first find the amount of OH- ions we have.

0.0137 L * 0.125 M = 0.0017125 moles of Sr(OH)2. Since there are 2 OH- ions for every Sr(OH2) molecule, we have 0.0017125*2 = 0.003425 moles of OH- ions. That means we also have 0.003425 moles of H+ ions.

Since there is only one H+ ion per molecule of HNO3, we have 0.003425 moles of HNO3.

0.003425 mol/0.025 L = 0.137 M.