A student titrates 0.100M KOH, potassium hydroxide, into 50.0ml of 0.10M HCOOH, formic acid (Ka=1.8 x 10^-4. What is the pH of the mixture after 25.0ml of the KOH has been added

1 answer

moles KOH initially = M x L = ??
moles HCOOH initially = M x L = ??

KOH + HCOOH ==> HCOOK + H2O
Use the above information on the first two lines to set up an ICE chart. then use the Henderson-Hasselbalch equation to solve for pH of the buffer solution that has been prepared.

The other way to do this is to realize that 25.0 mL is just half-way to the equivalence point which means pH = pKa.