Question

State the colour change which happens when acid or base is poured on phenolphthalein and methyl orange ?

Answer 1

Phenolphthalein is colourless in acidic solution and it changes its colour to pink in basic solutions but in weakly basic solution the pink colour becomes colourless after sometime.

Methyl orange is pink in acidic solution and it changes colour to yellow as the solution becomes increasingly basic in character, similar to phenolphthalein the yellow colour of Methyl orange becomes colourless after sometime.