(Solved): PRE-LAB QUESTIONS 1. Draw the molecular structure of glycine in the acidic solution. 2. In this la ...

PRE-LAB QUESTIONS 1. Draw the molecular structure of glycine in the acidic solution. 2. In this lab you will assess the volume (mL) of NaOH necessary to reach the isoelectric point (pl) of glycine. The isoelectric point is reached when the amino acid is neutral in overall charge. In this case, the carboxylic acid was deprotonated, and the amino group remained protonated. Draw the corre- sponding molecular structure (including all charges!) of glycine in solution. 3. The carboxylic acid functional group will act as a buffer inhibiting a substan- tial change in pH to the solution (until nearly all of the carboxylic acids are deprotonated by the NaOH). Explain how this buffering effect will impact the expected change in pH of the solution up to and immediately after 1 equiva- lent of NaOH is added. 4. Glycine has two pKa values. A pKa value describes the point at which a func- tional group is 50% protonated and 50% deprotonated. The lower a pKa value, the more easily the corresponding proton will be lost from the acid. pKa, cor- responds with the functional group which has the lowest pKa (the carboxylic acid of the original carbon chain). a. Explain why the pKa, of glycine is expected to be much lower than the pKa of acetic acid. b. Explain why the pKa, of glycine is expected to be much lower than the pl. C. Draw the two representative structures of glycine at pKa,.