Multiple choice

Hard water does not lather well with soap because

  1. it contains carbonates of calcium and magnesium

  2. it is highly coloured

  3. it contains suspended impurities

  4. it contains sodium chloride

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hard water contains calcium and magnesium ions that react with soap to form insoluble precipitates (scum) instead of lather.