Question

Prepare a theoretical titration curve for titration of 25.0 mL of 0.1037 formic acid (HCOOH; pKa = 3.75) solution (diluted to 100 mL volume with deionized water) by 0.0964 M solution of KOH. I have to determine volume of KOH needed to reach equivalence point, the pH of starting solution, the pH at equivalence point, graph it all somehow, and calculate pH points from equivalence point up until 150% of volume at eqivalence point and figure out if these points make a smooth curve? I just need some help on how to get started on this formulas and steps on what to do here

Answer 1

We can't draw figures on the board.
Write the reaction and balance it.
At the beginning, the pH is determined by the M of the formic acid. The beginning M is 0.1037 x (25.00 mL/100.0mL) = ? This gives you pH at zero mL base.

Next, determine where the equivalence point will be. That will be mL acid x M acid = mL base x M base. Solve for mL base. The concn of the salt will be moles acid at the beginning/L total volume (acid + 100 mL at start + volume base used to get to the eq point). Then write the hydrolysis equation for the salt and calculate the pH.

Everything past the eq point is just excess base modified by the dilution from the beginning to the point you are calculating.

Everything between the beginning and the eq point is determined by the Henderson-Hasselbalch equation.