Question

Arnav is provided with three kinds of liquid of them one is sodium hydroxide; another is hydrochloric acid and third is a sugar solution. How will he identify them when he have only red litmus paper Give one more example of natural indicator.

Answer 1

Answer:

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

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

There is no effect on turmeric solution by sugar solution.