When butter turns rancid, its foul odor is mostly that of butanoic acid, HCOOH, a weak monoprotic acid similar to acetic acid in structure. In a 0.0100 M solution of butanoic acid at 20°C, the acid is 4.0% ionized. Calculate the Ka of butanoic acid at this temperature.
Ka =
Calculate the pKa of butanoic acid at this temperature.
pKa =