From the graph find equivalence point, determine pH at half-equivalence point. Calculate Ka value of acetic acid. 2. Show pH calculations to verify your calculated pH values (before addition of NaOH), during titration (two pH values), at equivalence point, and after equivalence point (1 pH value). Make sure all appear in your lab report

Titration of a weak acid with a strong base: (acetic acid, NaOH): ChemCollective: http://www.chemcollective.org/ Materials needed: 1 M acetic acid, 1M NaOH, 250 mL Erlenmeyer flask, buret, phenolphthalein indicator. 1. Choose 1 M acetic acid and 1 M NaOH solution from stock solutions. 2. Transfer 25.0 mL of acetic acid to a 250 mL Erlenmeyer flask, write down the pH value in your table in observation #1. Add 0.3 mL of Phenolphthalein indicator to the flask. Duplicate this solution. Use one of the two solutions to do titration. 3. Transfer 50.0 mL of NaOH solution to a buret Titration: Transfer 5.0 mL of NaOH solution from the buret at a time to the flask containing 25.0 mL of acetic acid solution (one of the duplicate solutions) until you have added a total of 20.0 mL, then add 1.0 mL at a time until you have added a total of 24.0 mL of NaOH. Then add 0.2 mL at a time to reach 25.0 mL of NaOHà note down the observed pH value after each addition. Keep adding 1.0 mL of NaOH at a time to reach a total addition of 30.0 mL of sodium hydroxide. Make sure to write down pH values after each addition of NaOH solution. Take some pictures of your observed data value obtained in this experiment, and attach with your lab report. Pre-lab: read the procedure, construct a table having four columns 1)# of observations, 2) volume of NaOH added, 3)Total volume of NaOH and 4) observed pH value columns. All columns should be filled except the pH value column. A partial one is shown here # observation Vol of NaOH added, mL Total Vol of NaOH, mL pH 1 0 0 2 5.0 5.0 3 5.0 10.0 Etc. Post-lab: 1. plot pH values (y-axis) against total volume of added NaOH (column #3). From the graph find equivalence point, determine pH at half-equivalence point. Calculate Ka value of acetic acid. 2. Show pH calculations to verify your calculated pH values (before addition of NaOH), during titration (two pH values), at equivalence point, and after equivalence point (1 pH value). Make sure all appear in your lab report.