8.3 The pH scale

The pH scale

• pH scale is effective way of representing concentration of hydrogen ions [H⁺] in a solution
• It is a logarithmic scale with base 10, easy way for non-scientist to understand safety of materials
• pH distinguishes between acidic, neutral and alkaline

Calculating pH

• The concentration of an acid with one proton is the same as the concentration of hydrogen ions [H⁺]
  • [HCl] = [H⁺]
• For more protons:
  • [H₂SO₄] = 2[H⁺]

Ionization of water