 We're going to titrate a sample of phosphoric acid with a solution of sodium hydroxide. As an example of titrating a polyprotic acid, you're going to know the volume and the molarity of the phosphoric acid and the molarity of the sodium hydroxide solution. This should allow you to calculate the first half equivalence point, the first equivalence point, the second half equivalence point, the second equivalence point, the second half equivalence point, and the third equivalence point, and you should include those in your data collection. We're going to pipette 10 milliliters of a phosphoric acid solution. We know the volume and the molarity of the phosphoric acid, so we'll know the number of moles of phosphoric acid that we're using. We're also going to pipette in 50 milliliters of distilled water to give us enough volume to do our titration. We're going to place our calibrated pH electrode into the solution. We're going to gently stir the solution. We want to be careful that the stir bar does not hit the electrode. We've already calibrated the probe, so we're ready to collect data. We're going to come down to collect data. We're going to select trigger prompt. We're going to wait 30 seconds for the electronics to warm up. We're going to take an initial reading with zero milliliters of sodium hydroxide added. This will give us an initial pH of the phosphoric acid solution. When the CBL is stable, we're going to press trigger and enter the volume on our calculator 0.00 milliliters. We're now going to add as close to one milliliter of sodium hydroxide solution as possible. If you don't hit exactly one milliliter, simply read the volume and enter that volume into the calculator. When the CBL reading is stable, press trigger and enter the value on your calculator 1.00 milliliters. Want to collect more data? You're going to add the sodium hydroxide solution in one milliliter increments, collecting data each time. Remember that you also want to include in your titration the volumes for the first half equivalents, first equivalents, second half equivalents, second equivalents, third half equivalents, and third equivalents points in your data. When you reach 50 milliliters and the CBL reading is stable, press trigger on the CBL and enter the value in your calculator 50.00 milliliters. We're ready to stop collecting data. So arrow down to stop, press enter. This is the titration curve of the phosphoric acid with sodium hydroxide.