This is a simple online molarity calculator from the % purity and density of the concentrated acids and bases. I have developed this calculator for the calculations necessary for the preparation of solutions using concentrated acid or base solutions. Concentrated acids and bases such as sulfuric acid, hydrochloric acid, nitric acid, and ammonium hydroxides are provided with a certain % purity and a specific density. You can find these details on the label of the container.

Using the details; formula weight, percent purity, and density of an acid or base, you can calculate the molarity of the concentrated solution. However, it would be tedious to calculate the initial molarity of the concentrated acids and bases and use that molarity for the dilutions. Therefore, to minimize the time and avoid complex calculations, I developed it. Basically, it uses the molarity formula for the percent purity and density. The relationship of the molarity, formula weight, % purity, and density of the concentrated solution is given as

So, using the formula above, the given online molarity calculator determines the molarity of the initial concentrated acid or base. Then using the initial concentration (molarity), it calculates the required volume for the preparation of desired molar diluted solutions. Therefore, it contains two formulas; 1) a molarity calculator for the initially concentrated solutions, and 2) a dilution calculator for the volume required for the preparation of diluted solutions.

After entering the customized values of the selected acids or bases; % purity, density, formula weight, desired volume, and desired concentration, you can easily determine the required volume to make the desired solution.

For example, the % purity of the concentrated nitric acid is 70 %. Its density is 1.413 g/mL and its formula weight is 63.01 g/mol. So molarity of the 70% concentrated nitric acid will be 15.698 M. Then using the molarity value, of 15.698 M, it will be easy to calculate the required volume for the preparation of desired diluted solutions. The predefined values given in the fields are based on the information provided in sigma-Aldrich products. However, you may enter the same values in their respective fields or the values printed over the concentrated acids or bases that you are going to use for the preparation of diluted solutions.

So, take the required volume of the concentrated acid and bases in a volumetric flask and add the deionized water to make the final volume of the desired solution. Your solution of the desired concentration is ready. This formula applies to only some of the basic chemicals that are present in liquid forms such as acetic acid, nitric acid, sulfuric acid, phosphoric acid, perchloric acid, hydrochloric acid, hydrofluoric acid, formic acid, and ammonium hydroxide.