Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them? You have only turmeric indicator.

Turmeric solution is a natural indicator that turns red in contact with bases and is not affected by acids or neutral substances. Put one drop of each liquid on the turmeric paper. The liquid whose drop turns the paper red is sodium hydroxide (base).

Now, this red turmeric paper may be used to identify which of the two remaining liquids is hydrochloric acid. Put one drop of each of these remaining liquids on the red turmeric paper. The liquid whose drop will turn this red paper yellow is hydrochloric acid. This color changes from red to yellow because hydrochloric acid neutralizes the pH effect of sodium hydroxide on turmeric paper.

The sugar solution is neutral and will not show any change in color of turmeric indicator which has turned red.