Polyprotic Acid And Bases

Question 1

What is the simplest form of polypeptide acids

Answer 1

Diprotic

Question 2

What happens to the diprotic acid at lot ph
At high ph
At medium ph

Answer 2

Both groups deprotonated
Both groups protonated
Acid group deprotonated, amino group protonated (amphiprotic)

Question 3

For triprotic acids when is the concentration of h3a and ha2- equal

Answer 3

When H2a-is formed

Question 4

For triprotic acids when is the concentration of h2A- and A3- equal

Answer 4

When HA2- is made

Question 5

For diprotic acid what form dominates at low ph

Answer 5

H2A

Question 6

For diprotic acid what form dominates at high ph

Answer 6

A2-

Question 7

For diprotic acid what form dominates at mid ph

Answer 7

Ha-

Question 8

What is the isoelectric ph/point for polyprotic molecules, how to calc

Answer 8

The ph where the average charge of the polyprotic acid is zero

Ex( h2A=A-)

Use equation for ph of ha (assumption version)

Question 9

What is the isoionic ph/point for polyprotic molecules, how to calc

Answer 9

The ph of a pure neutral polyprotic acid in water

Ex. H2A doesn’t equal A-

Use equation for h+ of HA

Question 10

How is iso electric focusing of protiens done

Answer 10

To separate proteins:

The protien mix is added to a strong electric field with a ph gradient
Postive charge molecule more to negative end and vise versa
The protiens move until their ph is the same as it’s isoelectric ph

The the isoelectric point the protien has no charge so it doesn’t move