) Solution | Online Calculator

pH of Nitric Acid (HNO3) Solution | Online Calculator

Nitric acid is a strong oxidizing acid and it completely dissociates to the hydronium ions and nitrate ions in water to show strong acid characteristics. In this tutorial, we are looking to study how to calculate pH of aqueous nitric acid solutions.

Complete dissociation of nitric acid in water

HNO3(aq) + H2O(l) → H3O+(aq) + NO3-(aq)

In this tutorial we will cover following sections.

  1. pH values of different concentrations aqueous HNO3 solutions
  2. Two online calculators to calculate pH value of HNO3
  3. Solving a problem of how to calculate pH of HNO3

pH values of different concentrations aqueous HNO3 acid solutions

Concentration (mol dm-3) pH
0.1 1
0.05 1.30
0.01 2
0.005 2.30
0.001 3
1 0

Online pH Calculator for HNO3 acid

According to the data you know, you can use a suitable calculator to calculate pH value.

When concentration is known in mol dm-3

you can enter the concentration of HNO3 acid in mol dm-3 and check the pH value.


Note: This online calculation is not suitable for very dilute solutions of HNO3 (such as 0.0000005 mol dm-3) because, those solutions give very low H+ ion concentration. In those cases, pH value is very close to the neutral value of seven.

Calculate pH when density and weight fraction (w/w %) of HNO3 solution is known


Calculate pH of HNO3 using the pH equation

Because HNO3 is a strong acid, it dissociates completely to H+ and NO3- ions in the water.

HNO3 → H+ + NO3-

According to the stoichiometric ratios, H+ concentration equals to the HNO3 concentration. Therefore, we can directly substitute HNO3 concentration to pH calculation equation.

pH = -log10[H+(aq)]

We can write above equation for HNO3 as below.

pH = -log10[HNO3(aq)]

pH of 0.1 mol dm-3 HNO3 solution

  • pH = -log10[0.1]
  • pH = 1

You can see, 0.1 mol dm-3 HNO3 acid solution is strong acidic solution because pH value is well below seven.