Phenolphthalein is a commonly used indicator that is colorless inthe acidic form (pH < 8.3) and pink in the basic form (pH >10.0). It is a weak acid with a pKa of 8.7.
A) What is the ratio of the conjugate base concentration to the acid concentration, that is, [B- ]/[HB] when the indicator switches to the acidic color?
B) Use the result to the above question to determine what percent is in the acidic form when the acid color is first apparent?