Phenolphthalein is a pH indicator that turns pink in basic solutions, and colorless in acidic solutions. Normal pH of saliva ranges between 6.2 (acidic) and 7.4 (basic), with 7 being neutral pH. So,...
Nothing happens when any acid is added to Phenolphthalein. ;)
it will turn pink. phenophathaline turns pink in alkaline ph
it turns into a pinkish red color
Giving the context where these a,b and main are mentioned would make more sense and be responded with clear answers please.