Chemistry Question

Question

Consider the neutralization reaction 2HNO3 (aq)+Ba(OH)2 (aq)------>2H₂O(l)+Ba(NO₃)₂(aq).

A 0.115-L sample of an unknown HNO3 solution required 41.9 mL of 0.150 M Ba(OH)2 for complete neutralization. What was the concentration of the HNO3 solution?

Answer 1

2HNO₃ (aq)+Ba(OH)₂ (aq)------>2H₂O(l)+Ba(NO₃)₂(aq).

moles Ba(OH)2 used = 0.0419 L x 0.150 mol/L = 0.006285 moles

Now find moles of HNO₃:

0.006285 mole Ba(OH)₂ x 2 mole HNO₃/mol Ba(OH)₂ = 0.01257 moles HNO₃

Concentration of HNO₃ = 0.01257 moles/0.115 L = 0.109 M (to 3 significant figures)