Complete pKa Values

Question 1

carbon chain/carbon chain with a negatively charged carbon on the end

Answer 1

50, strong base, good Nu

Question 2

NH3/NH2-

Answer 2

38, strong base, good Nu

Question 3

H2/H-

Answer 3

35, strong base, good Nu

Question 4

///C-H / ///C-

Answer 4

25, strong base, good Nu

Question 5

alcohol (OH) / O-

Answer 5

16, strong base, good Nu

Question 6

H2O/OH-

Answer 6

15.7, strong base, good Nu

Question 7

H-NR3+/NR3

Answer 7

11, weak base, good Nu

Question 8

H-S-R/H-S(-)-R

Answer 8

10, weak base, good Nu

Question 9

NH4+/NH3

Answer 9

9.4, weak base, good Nu

Question 10

HCN/CN-

Answer 10

9, weak base, good Nu

Question 11

H2S/HS-

Answer 11

7, weak base, good Nu

Question 12

HN3/N3-

Answer 12

5, weak base, good Nu

Question 13

OOH/OO- (carboxyllic acid and CB)

Answer 13

4.8, weak base, weak Nu

Question 14

H3O+/H2O

Answer 14

-2, weak base, weak Nu

Question 15

TsOH/TsO-

Answer 15

-7, weak base, weak Nu

Question 16

HCl/Cl-

Answer 16

-7, weak base, weak Nu

Question 17

HBr/Br-

Answer 17

-9, weak base, weak Nu

Question 18

HI/I-

Answer 18

-10, weak base, weak Nu

Question 19

What are the nucleophiles that are weak enough to take part in an SN1 reaction? (base form since that is how they are as nucelophiles)

Answer 19

OO-, water, TsO-, Cl-, Br-, I-

Question 20

What are the weak bases that are still good Nu?

Answer 20

N3, NH3, NR3, CN-, HS-, HS(-)R

Question 21

What is the pKa boundary between strong and weak bases?

Answer 21

any pKa lower than 15 (lower than water/alcohols) is a weak base (because it is a strong acid)

Question 22

What is the pKa boundary between good and bad nucleophiles?

Answer 22

any pKa lower than carboxyllic acid’s CB (lower than 4.8) is a very strong acid so a very weak nucleophile