A student prepared solutions of
(i) an acid and
(ii) a base in two separate beakers.
She forgot to label the solutions, and litmus paper is not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?

AcademicChemistryNCERTClass 10

Phenolphthalein can be used to check the beakers that contain acid and which one contains a base as it turns colourless in acidic solutions and pink in basic solutions.

Natural indicators; like China rose or turmeric can also be used.

Turmeric is a natural indicator. Turmeric is of yellow colour. Turmeric paper turns red when it is dipped into a basic solution. Turmeric paper does not change its colour with acid.

China rose is also a natural indicator that can be used. China rose solution gives dark pink (magenta) colour with acid and green colour with base.
Updated on 10-Oct-2022 13:27:15