Mnemonic Device for Colour change of Litmus Paper on Acid and Base

This is scientific fact that Acid turns Blue Litmus To Red.

We can use the bold words AB-TR to remember the colour change of acid and bases on red or blue litmus paper. I hope you have watched AVATAR; a very popular English movie. I am sure you guessed what I am going to tell. Yes!! That's right. AB-TR can be pronounced in the same way as AVATAR. So you just need to remember AB-TR from which you can remember that Acid turns Blue Litmus To Red.