pH

pH is a scale used to measure the acidity or basicity (alkalinity) of an aqueous solution. It ranges from 0 to 14 and is calculated based on the concentration of hydrogen ions (H+\text{H}^+H+) in the solution. Here’s what the pH scale means:

• pH < 7: The solution is acidic (higher concentration of H+\text{H}^+H+ ions).
• pH = 7: The solution is neutral (equal concentrations of H+\text{H}^+H+ and OH−\text{OH}^-OH−).
• pH > 7: The solution is basic (higher concentration of OH−\text{OH}^-OH− ions).

Mathematical Definition:

The pH is defined as:

pH=−log⁡10[H+]\text{pH} = -\log_{10} [\text{H}^+]pH=−log10​[H+]Where:

• [H+][\text{H}^+][H+] is the molar concentration of hydrogen ions in the solution.

Examples:

• Lemon juice: pH ≈ 2 (acidic)
• Pure water: pH = 7 (neutral)
• Baking soda solution: pH ≈ 9 (basic)

The pH scale is logarithmic, meaning that each whole number change represents a tenfold change in H+\text{H}^+H+ concentration. For example, a solution with a pH of 4 is ten times more acidic than a solution with a pH of 5.

Let me know if you’d like more details about pH measurement or related topics!