Which of the following scale is used to measure the hydrogen ion concentration in a solution?

pH scale

The correct answer is option 1. pH scale.

The pH scale is a logarithmic scale used to specify the acidity or alkalinity of a solution. It measures the concentration of hydrogen ions (\(H^+\)) in a solution. The pH scale ranges from 0 to 14, where:

• A pH of 7 represents a neutral solution, where the concentration of hydrogen ions (\(H^+\)) is equal to the concentration of hydroxide ions (\(OH^-\)).
• A pH below 7 indicates acidity, meaning there are more hydrogen ions (\(H^+\)) than hydroxide ions (\(OH^-\)) in the solution. The lower the pH value, the higher the acidity of the solution.
• A pH above 7 indicates alkalinity (basicity), meaning there are more hydroxide ions (\(OH^-\)) than hydrogen ions (\(H^+\)) in the solution. The higher the pH value, the higher the alkalinity of the solution.

The pH scale is logarithmic, meaning that each whole number change in pH represents a tenfold change in the concentration of hydrogen ions (\(H^+\)). For example, a solution with a pH of 3 has 10 times more hydrogen ions than a solution with a pH of 4, and 100 times more hydrogen ions than a solution with a pH of 5.

The pH scale is widely used in various fields, including chemistry, biology, environmental science, and medicine, to assess the acidity or alkalinity of solutions and to monitor chemical reactions, biological processes, and environmental conditions.