Strong/weak acid pH Calculator app for iPhone and iPad

Calculating the pH of an acidic solution is a fundamental aspect of the chemistry laboratory. This app can calculate the pH of a strong acid solution given the concentration of the strong acid of choice. Calculating the pH of a weak acid is more complicated because weak acids do not completely disassociate in solution. For example, the pH of an aqueous benzoic acid solution, a weak acid commonly used in perfumes, dyes, topical medications and insect repellents must be calculated using the disassociation constant (Ka) relationship. Ultimately, the quadratic formula must be used to solve for the concentration of hydrogen ions in solution. However, a quicker method exists if the concentration of the weak acid in solution is orders of magnitude greater than the Ka. In other words, if the concentration of the weak acid is at least 10 times greater than the Ka, the calculation can be simplified. This app determines if the simplification can be utilized and calculates the pH of the solution given the Ka and concentration of the weak acid.