What is the formula used to calculate the pH of a solution?

The formula used to calculate the pH of a solution is given by pH = -log[H+]. This equation indicates that pH is the negative logarithm of the concentration of hydrogen ions [H+] in a solution.

The reason this formula is essential is that pH is a logarithmic scale that quantifies the acidity or basicity of an aqueous solution. When the concentration of hydrogen ions increases, the pH value decreases, meaning the solution becomes more acidic. Conversely, a lower concentration of hydrogen ions results in a higher pH and indicates a more basic or alkaline solution. The use of a logarithmic function allows for a more manageable range of values, as hydrogen ion concentrations can span many orders of magnitude.

This formula is fundamental in chemistry, particularly in acid-base theory, because it succinctly captures the relationship between hydrogen ion concentration and pH, which is crucial for various chemical calculations and reactions.