Multiple choice

The effectiveness of soap is reduced when it is used in

  1. hot water

  2. warm water

  3. hard water

  4. soft water

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

Correct Answer: hard water Soap is not an effective cleansing agent when used with hard water, as the calcium and magnesium ions in the hard water form insoluble salts with soap which stick to the cloth as scum.