What is the resulting hydronium ion concentration and the resulting molarity of the base solution of a given reaction?

Question

10 cm³ of a 2M solution of nitric acid (HNO₃ (aq) ) is added to 10 cm³ of a 1M solution of calcium hydroxide (Ca(OH)₂ (aq) ) solution.

a)    What is the resulting total volume?

b)    What is the resulting hydronium ion concentration (assume no hydrolysis occurs in the salt-water interaction)

c) What is the resulting molarity of the base solution after the reaction has occurred (assuming the reaction to be complete to the right)?

Answer 1

2HNO₃(aq) + Ca(OH)₂(aq) ==> 2H₂O(l) + Ca(NO₃)₂(aq) .. balanced equation

(a). total volume = 10 ml + 10 ml = 20 ml (0.020 L)

(b). mols HNO₃ = 10 ml x 1 L / 1000 ml x 2 mol / L = 0.02 mol

mols Ca(OH)₂ = 10 ml x 1 L / 1000 ml x 1 mol / L = 0.01 mol

mols HNO₃ neutralized = 0.01 mol Ca(OH)₂ x 2 mol HNO₃ / mol Ca(OH)₂ = 0.02 mol HNO₃ neutralized

mols HNO₃ left over after reaction = 0 mols

resulting [H3O+] assuming no salt-water interaction = 1x10-7 M

(c). mols Ca(OH)₂ reacted (neutralized) = 0.02 mol HNO₃ x 1 mol Ca(OH)₂ / 2 mol HNO₃ = 0.01 mol

mols Ca(OH)₂ remaining = 0 mols

resulting [Ca(OH)₂] after reaction = 0