試題詳解

15. A 0.210-g sample of an acid (molar mass = 192 g/mol) is titrated with 30.5 mL of 0.108 M NaOH to a phenolphthalein endpoint. The formula of the acid is
(A) H₃A
(B) H₂A
(C) H₄A
(D) HA
(E) not enough information given