Neutralizing Reactions

Question

Consider the neutralization reaction :

2HNO3(aq)+Ba(OH)2(aq)⟶2H2O(l)+Ba(NO3)2(aq)

A 0.110 L sample of an unknown HNO3 solution required 43.5 mL of 0.150 M Ba(OH)2 for complete neutralization. What is the concentration of the HNO3 solution?

Answer 1

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

moles Ba(OH)₂ used = 43.5 ml x 1 L / 1000 mls x 0.150 mols / L = 0.006525 moles

moles HNO₃ present = 0.006525 mols Ba(OH)₂ x 2 mols HNO₃ / mol Ba(OH)₂ = 0.01305 mols

Concentration HNO₃ = moles / L = 0.01305 mols / 0.110 L = 0.119 M (3 sig. fgis.)