Multiple choice

In which of the following is hard water produced?

  1. Saturation of water with calcium carbonate

  2. Saturation of water with magnesium carbonate

  3. Saturation of water with calcium sulphate

  4. Addition of sodium sulphate to water

  5. None of these

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

Ca and Mg soluble sulphates and chlorides cause permanent hardness.