What is the pH scale and how is it related to acid-base equilibria?

The pH scale measures the acidity or alkalinity of a solution. It is related to acid-base equilibria because it is a logarithmic scale that measures the concentration of hydrogen ions (H+) in a solution.

Acids are substances that release hydrogen ions (H+) when dissolved in water, while bases are substances that release hydroxide ions (OH-) when dissolved in water. The pH scale ranges from 0 to 14, with 0 being the most acidic, 7 being neutral, and 14 being the most alkaline.

The pH of a solution can be calculated using the formula pH = -log[H+], where [H+] is the concentration of hydrogen ions in moles per litre. For example, a solution with a pH of 3 has a hydrogen ion concentration of 10^-3 moles per litre.

Acid-base equilibria refer to the balance between the concentration of hydrogen ions and hydroxide ions in a solution. The pH of a solution can affect the equilibrium of acid-base reactions, as the concentration of hydrogen ions determines the strength of an acid and the concentration of hydroxide ions determines the strength of a base.

The pH scale is important in many biological processes, as enzymes and other proteins have specific pH ranges in which they function optimally. Deviations from these pH ranges can denature proteins and disrupt cellular processes. Understanding the pH scale and acid-base equilibria is therefore crucial in the study of biology.