pKa values

Question 1

A stronger acid has a ? pka?

A better leaving group has a ? pKaH?

Answer 1

Stronger acid → lower pH → higher Ka → lower pKa

Lower pKaH → leaving group has a stronger conjugate acid → better leaving group

The pKaH is the pKa of the leaving group’s conjugate acid. So an acid’s pKa = its base’s pKaH.

Question 2

for all following acids and pka values, remember that the pka of acid = pkah of conjugate base

Question 3

HI

Answer 3

-10

Question 4

HCl

Answer 4

-7

Question 5

H₂SO₄

Answer 5

-3

Question 6

H₃O⁺

Answer 6

-1.7

Question 7

HSO₄^-

Answer 7

2

Question 8

carb acids

Answer 8

~5

Question 9

H₂S

Answer 9

7

Question 10

HCN

Answer 10

9.1

Question 11

NH₄⁺

Answer 11

9.2

Question 12

phenol

Answer 12

10

Question 13

H₂O

Answer 13

15.7

Question 14

ethanol

Answer 14

15.9

Question 15

ketones

Answer 15

~20

Question 16

alkynes

Answer 16

~24

Question 17

ammonia/amines

Answer 17

~33

Question 18

H₂

Answer 18

35

Question 19

benzene

Answer 19

43

Question 20

alkanes

Answer 20

48-60