Acids and Bases

pH - potential of Hydrogen

pH measures how acidic or basic a substance is, using a scale from 0 to 14.

A pH of 7 is neutral, below 7 is acidic, and above 7 is basic (alkaline).

Acids

• Acids have a pH less than 7 and produce H⁺ ions in water.

• Acids release hydrogen ions (H⁺) when dissolved in water, making the solution more acidic.

• The more H⁺ ions in a solution, the stronger the acid.

Bases

• Bases have a pH greater than 7 and produce OH⁻ ions in water.

• Bases release hydroxide ions (OH⁻) when dissolved in water, making the solution more alkaline.

• Strong bases can neutralize acids by reacting with H⁺ ions to form water.

Weak acids and bases partially dissociate, releasing fewer ions (e.g., vinegar, ammonia).

Weak

Strong acids and bases fully dissociate in water, releasing more H⁺ or OH⁻ ions e.g., HCl, NaOH.

Strong

Neutralisation Reaction

When acids and bases react, they form water and a salt. This is called neutralisation.

Example: HCl + NaOH → NaCl + H₂O