An aqueous nitric acid solution has a pH of 2.15.What mass of HNO₃ is present in 20.0 L of this solution?

Question

Quizplus · Accepted Answer

The pH of 2.15 corresponds to a hydrogen ion concentration of 10^-2.15 M. For HNO3, which dissociates completely, this is also the concentration of HNO3. Thus, the concentration is approximately 0.00708 M. Multiplying by the volume (20.0 L) gives moles of HNO3, which is 0.1416 moles. The molar mass of HNO3 is 63.01 g/mol, so the mass is 0.1416 moles * 63.01 g/mol = 8.9 g.

An Aqueous Nitric Acid Solution Has a PH of 2