MEPX
Chapter 5 of 10All chapters
  1. 1Atoms
  2. 2The periodic table
  3. 3Bonding
  4. 4Reactions
  5. 5Acids and bases
  6. 6States of matter
  7. 7Mixtures and separation
  8. 8Organic chemistry
  9. 9Chemistry around you
  10. 10Working safely

Chapter 5 of 10

Acids and bases

The pH scale.

What pH means

Acids release hydrogen ions in water and bases accept them. The pH scale runs from 0 to 14 with 7 neutral, and it is logarithmic, so each step is a factor of ten.

  • Stomach acid is around pH 2; household bleach is around pH 13.
  • Strong and concentrated are different: strength is how completely it dissociates.

Neutralisation

An acid and a base react to give a salt and water, releasing heat. Indigestion remedies, soil treatment and much of industrial chemistry rest on this one reaction.