Polyprotic Acid-Base Equilibria

Question 1

A common class of diprotic acids

Answer 1

amino acids

Question 2

zwitterion

Answer 2

has both positive and negative
sites

Question 3

pH of Diprotic Buffers

Answer 3

pH~1/2(pKa1 + pKa2)

Question 4

isoionic point

Answer 4

pH obtained when the pure, neutral polyprotic acid HA (the neutral
zwitterion) is dissolved in water.
– The only ions are H2A+, A-, H+, and OH-.

Question 5

isoelectric point

Answer 5

pH at which the average charge of the polyprotic acid is 0.
– Most of the molecules are in the uncharged form HA, and the
concentrations of H2A+ and A- are equal to each other.
[H2A+ ] = [A-]