Here it says consider the titration of Sony 5 MLS of 0.0300 molar of pyruvic acid. Here the KA is 4.1×10-3 and we're reacting it with 75 M LS of 0.0450 molar of potassium hydroxide. Calculate the pH. All right, so we have a weak species reacting with a strong species, so we know we need to set up an ICF chart. The strong species has to be set as a reactant, so potassium hydroxide has to be a reactant. It reacts with its chemical opposite, so it reacts with the pyruvic acid.

Now, following the Bronsted-Lowry definition, the acid would protonate or donate an H to the base. That will give us water as a byproduct as the H combines with the OH^- and then the potassium will combine with the pyruvate to give us potassium pyruvate. Now we're going to say that this is an ICF, so that's initial change, final with an ICF chart. We need our units to be in moles. Divide your MLS by 1000 to get liters, because remember moles equals liters times molarity.

So when we do that, we're going to get 0.00225 moles of our weak acid and then we're going to have 0.003375 of our strong base. We have zero of our conjugate initially and the 4th species we don't care about. Now here, look at the reactants. The smaller moles subtract from the larger moles, so minus OH 0.00225, minus 0.00225. So at the end, we have no weak acid remaining, but we're going to have some strong baseline. Whatever we lose on the reactant side, we gain on the product side based on the law of conservation of mass.

Now at the end, what do we have? We have strong base conjugate base. The strong species will have a larger impact on our overall pH. So focus on the strong species. So we have here, using the final row, determine the concentration of the strong base. Divide its final moles by the total volume used in a chemical reaction. So what do we have here? We have 0.001125 moles of potassium hydroxide divided by the total volume. The total volume is 75 MLS, 75 MLS, so that's 150 MLS. When you divide that by 1000, that gives you 150 liters.

So. So that'll give me my new concentration, which is 0.0075 molar for my strong bings. Now this is important because recall the concentration of the strong base will be equal to the concentration of OH^-. So we just found out the concentration of OH^- is this number. If we know OH concentration, that's good because that will help me find pOH. So pOH equals negative log of OH^-. So plug that number in. So that's going to give me 2.12. If I know pOH then I know pH because of this formula. So pH if we rewrite it equals 14 minus pOH, so it's 14 - 2.12 which comes out to 11.88. So this will represent the pH of my solution after the equivalence point.