2HNO3(aq)+Ba(OH)2(aq)⟶2H2O(l)+Ba(NO3)2(aq).A 0.115 L sample of an unknown HNO3 solution required 31.7 mL of 0.200 M Ba(OH)2 for complete neutralization. What is the concentration of the HNO3 solution?

Answer 1

Hello, Bri,

Be careful with the volume units. We are given ml, but the definition for Molar is moles/Liter.

We can calculate the number of moles in the 31.7 ml of Barium Hydroxide by multiplying the concentration by the volume in liters. The balanced equation says we only need one mole of Ba(OH)2 to react with two moles of HNO3. So if 0.00634 moles of Ba(OH)2 are used, then we must have twice that number of HNO3.

Take the moles of NHO3 and divide it by the total volume (in L) to get concentration. We are limited to 3 sig figs, so the concentration is 0.110M.

Bob