Question

Fill in the blanks
When we use blue litmus paper as an indicator, it give____ colour with base

Answer 1

Litmus paper is an indicator . It is used as an indicator to test the acidity of a substance and accordingly it gives colour according to the substance.

Complete step-by-step answer: We know that a litmus paper is an indicator used to identify the acidic substance. It accordingly changes the colour in the substance. The blue litmus paper is used to test the acidic nature and will turn the red colour in acidic solutions. For basic solutions it will not change the colour.
In acidic conditions it will turn to red colour and for base it will not change its colour. So the strip of paper will remain blue if we use blue litmus paper as an indicator.

Additional Information: Generally a litmus paper is used as a indicator for chemical reactions. However it causes a colour change even though the chemical reaction is not a acid base reaction.

Hence when we use blue litmus as an indicator it will give blue colour with base.

Note: Litmus paper is a paper that can be obtained from a water soluble dye obtained from lichens. It is used as a pH indicator .Also neutral litmus paper is purplish in nature and turns red under acidic conditions and blue under alkaline conditions.