A student placed a pinch of solid sodium hydrogencarbonate on a strip of red litmus paper. He found that the colour of red litmus paper strip:

What is the colour of red litmus.

What is the colour of red litmus in base?

Solid sodium bicarbonate was placed on a strip of pH paper. The colour of the trip:

A student placed a few drops of a liquid over a portiin of the red litmus paper as shwon here. He observed that the red litmus paper turned blue. The liquid could b: