Answer: The colour of red litmus paper changes to blue indicates that the chemical is a base. If there is no change in colour, then it is either acidic or neutral. We can easily identify a base.
- Mark the three test tubes as A, B, and C.
- Take a drop of the solution A and put it on the red litmus paper. Repeat the same process iwth solution B and C.
- If any of them changes colour to blue, then it is a base.And remaining two are acid and neutral.
- Now take a drop from the identified base and mix it with a drop taken from the remaining two solutions separately.
- Check the drops of the mixtures on red litmus paper.
- If the colour of red litmus turns blue, then the second solution is neutral. If it does not change colour, then the second solution is acid. This is because acidic and basic solutions neutralize each other.