From the ancient times acids and bases are characterized by the application of Litmus Paper.
We have present you the Concept of acid base in the Following PDF
https://drive.google.com/file/d/14xR2CtH4_ZLNBIk56bYDn7scdjybFKuc/view?usp=drivesdk
We have present you the Concept of acid base in the Following PDF
https://drive.google.com/file/d/14xR2CtH4_ZLNBIk56bYDn7scdjybFKuc/view?usp=drivesdk