A Weak Acid Is Titrated with a Strong Base to the Equivalence

Multiple Choice

A weak acid is titrated with a strong base to the equivalence point.The pH of the resulting solution is found to be 9.18.The pK_a of the acid is

A) 9.18.
B) 7.00.
C) 4.59.
D) 2.50.
E) 6.28.