Acid & Base Normality and Molarity Calculator

Acid and Base Solution Preparation

This calculator provides lab-ready directions describing how to prepare an acid or base solution of specified molarity (M) or normality (N) from a concentrated acid or base solution. To prepare a solution from a solid reagent, please use the Mass Molarity Calculator. To dilute a solution of known molarity, please use the Solution Dilution Calculator.

How is the Molarity of a percentage solution calculated?

Using 70% concentrated nitric acid as an example: 70% nitric acid means that 100 grams of this acid contains 70 grams of HNO₃. The concentration is expressed at 70% wt./wt. or 70 wt. % HNO₃. Some chemists and analysts prefer to work in acid concentration units of Molarity (moles/liter). To calculate the molarity of a 70 wt. % nitric acid the number of moles of HNO₃ present in 1 liter of acid needs to be calculated. Knowing the density of the acid to be 1.413 g/mL, we can calculate the weight of 1 L of 70% HNO₃ to be 1413 grams. Knowing that the solution is 70 wt % would then allow the number of grams of HNO₃ to be calculated: (0.700)(1413g) = 989.1 grams HNO₃ per liter. Dividing the grams of HNO₃ by the molecular weight of HNO₃ (63.01 g/mole) gives the number of moles of HNO₃ / L or Molarity, which is 15.7 M.

What is the equation used for Molarity Conversion?

The following equation is used for calculating acid and base molarity where the concentration is given in wt %:
[(% × d) / MW] × 10 = Molarity
Where: % = Weight %; d = Density (or specific gravity); MW = Molecular Weight (or Formula Weight).
The above equation can then be used to calculate the Molarity of the 70 wt % Nitric Acid:
[(70 × 1.413) / 63.01] × 10 = 15.7 M

How do I calculate the Normality of an acid or base from its Molarity?

There is a relationship between normality and molarity. Normality can only be calculated when we deal with reactions, because normality is a function of equivalents. Normality refers to compounds that have multiple chemical functionalities, such as sulfuric acid, H₂SO₄. A 1 M solution of H₂SO₄ will contain one mole of H₂SO₄ in 1 liter of solution, but if the solution is titrated with a base, it will be shown to contain two moles of acid. This is because a single molecule of H₂SO₄ contains two acidic protons (H+ Ions). Thus, a 1 M solution of H₂SO₄ will be 2 N. The normality of a solution is the molarity multiplied by the number of equivalents per mole.

Why does the calculator use 56.6% weight percentage instead of 28% for ammonium hydroxide?

28% ammonia (NH₃) is equal to approximately 56.6% ammonium hydroxide. Our product data (AX1303) reports the % ammonia and not the % ammonium hydroxide. Our calculator is designed to use the % ammonium hydroxide.