a 1.502 g sample of primary khp (potassium hydrogen phathlate; molar mass 204.23 g/mol) was weighed out into a 250 ml beaker and diluted with 50 ml of distilled water. several drops of phenolphthalein indicator were added to the solution, which remained colorless. a buret was filled with a solution of approximately 0.5 m sodium hydroxide naoh. the initial volume reading on the filled buret was 4.56 ml. the titrant, naoh, was used to titrate the khp in the beaker with phenolphthalein indicator. when the buret read 22.31 ml, the solution changed from colorless to pink. determine the concentration in m of the standardized naoh.