OCHEM I pKA values, names, conjugate base

Exam I

HI

-10

Hydroiodic Acid

I^-

6 Common Strong Acids

HBr

-9

Hydrobromic Acid

Br^-

Six Common Strong Acids

HCl

-8

Hydrochloric Acid

Cl^-

Six Common Strong Acids

HF

+3.2

Hydrofluoric Acid

F^-

H₂SO₄

-3

Sulfuric Acid

HSO₄^-

6 Common Strong acids

H₃O⁺

-2

Hydronium Ion

H₂O

Amphoteric

HNO₃

-1.4

Nitric Acid

NO₃^-

6 Common Strong Acids

H₂S

+7

Hydrogen Sulfide

HS^-

Weak, Inorganic

NH₄⁺

+9

Ammonium

NH₃

Weak, Inorganic

H₂O

+16

Water

OH^-

Amphoteric

ROH₂⁺

-2

“R” is generic for an alkyl group; generic alcohol

ROH

ROH

+16

“R” is generic for an alkyl group; generic alcohol

RO^-

The smaller the pKA value…

the more acidic and stronger the acid

The more acidic/stronger an acid…

the more stable/weaker it’s conjugate base is

The less acidic an acid…

The stronger, and more unstable it’s conjugate base is

The more stable/weaker the base…

The more acidic its conjugate acid will be

In proton transfer reactions, which side does equilibrium favor?

The side with the weaker, more stable base and the weaker weaker acid (higher pKA value)

+5

“R” is CH₃—> pKA= +4.7

+10

Benzenol

-3

4-methyl sulfonic Acid

+50

Methane

H₃C^-

+44

Ethene

H₂C=CH^-

+25

Ethyne

HCCH

>+60

Tertiary Carbon, or Methine Carbon

R₃C^-

+9.2

Hydrogen Cyanide

+20

Acetyl Group

+40

Ethyl Group

+10

Anhydride

NH₃

+35

Ammonia

NH₂^-