Acids and Bases

Question 0

What is a Lewis Acid?

Answer 0

Electron pair acceptor

Question 1

What is the definition of a Brønsted-Lowry acid?

Answer 1

Proton donor

Question 2

What is the pka of a carboxylic acid?

Answer 2

2-4

Question 3

What is the pka of a phenol? (benzene ring with OH)

Answer 3

10

Question 4

What is the pka of sulfonamide?

Answer 4

8-10

Question 5

What is the pka of an imide?

Answer 5

8-10

Question 6

What is the pka of a primary amine?

Answer 6

9-10

Question 7

What is the pka of a secondary amine?

Answer 7

9-10

Question 8

What is the pka of a tertiary amine?

Answer 8

9-10

Question 9

What is the pka of a quaternary amine?

Answer 9

n/a as at all pHs it exists as a cationic species

Question 10

What is the pka of an aromatic amine?

Answer 10

2-4

Question 11

What is the pka of pyridine?

Answer 11

~5.5

Question 12

What is the pka of an imidazole?

Answer 12

6-7

Question 13

How do you calculate concentration of hydrogen ions?

Answer 13

10^-pH

Question 14

How do you calculate isoelectric point?

Answer 14

(pka+pka)/2

Question 15

What are simple buffers?

Answer 15

Resist major changes in pH. Will only buffer effectively over the pH range of + or - 1.0

Question 16

What is a universal buffer?

Answer 16

It buffers over a wider pH range. Used with substances that have two or more functional groups that their pka values are separated by at least 2 pka units.

Question 17

Why are primary amines more basic than ammonia?

Answer 17

Addition of a methyl group (electron donating) increases the electron density around the nitrogen, making it easier to donate the electron.

Question 18

Why is a tertiary amine less basic than primary amines?

Answer 18

It is a larger compound, so a steric effect is present and there is no space to fit a H+.