1. It took 37.50 mL of NaOH to titrate 0.9061 g of primary standard KHP (FW 204.23). Calculate the molarity of the NaOH solution.
2. It took exactly 33.90 mL of 0.1180 M NaOH to titrate a 0.1801 gram sample of an unknown diprotic organic acid. What is its formula weight?
3. A 0.2341 gram sample of a diprotic organic acid was titrated with 0.100 M NaOH using a pH meter to generate the pH titration curve on the next page.
a. What is the FW of the acid?
b. What are the pKa1and pKa2 values for the acid?
c. What should the pH be at halfway to the 2nd equivalence point of the titration?
Part B
1. A 0.0352 g sample of pure calcium carbonate (100.09 g/mol) was dissolved in acid and titrated to its endpoint with newly made EDTA titrant (~0.010 M) according to the procedure given below. The starting burette volume was 0.10 mL. The ending burette volume was 35.52 mL. Calculate the exact concentration of the EDTA titrant. Show all work.
2. A 0.0456 g sample of an unknown sample was titrated using the EDTA titrant from question 1 and the procedure below. The starting burette volume was 0.05 mL. The ending burette volume was 42.35 mL. Calculate the % calcium oxide (CaO; 56.0774 g/mol) by mass in the sample. Show all work.
3. 100.0 mL of an unknown water sample was titrated using the EDTA from question 1 and the procedure below. The starting volume was 0.25 mL and the ending volume was 20.53 mL. Calculate the concentration of Ca2+ in the tap water. Show all work.