Question

how does the colour change when Litmus is treated with acidic or basic medium

Answer 1

when blue litmus is treated with acid, it colour changes to red.While when red litmus is dipped in base, it's colour changes to blue

Answer 2

If chemical is acidic(contains H+ ions) then the colour of litmus paper is red gives red, blue gives red. And if chemical is basic (oH-) then blue gives blue and in red gives blue.