0.272 g of a monoprotic solid acid (mw e 189 g/mol) is dissolved in water to produce 25.0 tut of a solution with pH = 4.93. Determine the ionization constant of the acid.

A) 4.1 x 10 ^-8

B) 2.4 x 10 ^-9

C)1 x 10 ^-4

D) 2.8 x 10 ^-7

E) 1.4 x 10 ^-10