Question

phenolphthalein indicator is a.r. indicator

Answer 1

on treating base with phenolphthalein it turns pink and on treating with acid it is colourless

Answer 2

Oxygen indicators reveal the presence or absence of oxygen by changing color. When the pink colored indicator is first removed from its protective packaging and exposed to an oxygen rich environment it will turn blue in color within a few minutes. After placing it within a sealed treatment bag with the proper amount of Ageless, the oxygen indicator will gradually return to its pink color over a period of 2-5 hours or when the oxygen content of the treatment bag reaches less than 0.01%. Reuse of the oxygen indicators is not recommended and do not purchase more indicators than you can use in a 6-12 month period. It's also recommended that you store the eyes in a cool dark place such as a refrigerator.