pKa and Acid Strength Reference Table

Vocabulary flashcards covering the definition of pKa, acid strength trends, and specific pKa values of common organic and inorganic compounds.

pKa

A measure of the strength of an acid.

Acid Strength and pKa Relationship

The lower the $pKa$ ($\downarrow pKa$), the stronger the acid.

$H_2SO_4$ (pKa)

$$-7$$

$R_2OH^+$ (Ether) (pKa)

$$-2 \text{ to } -3$$

$CH_3OH_2^+$ (pKa)

$$-2.0 \text{ to } -2.5$$

$H_3O^+$ (pKa)

$$-1.7 \text{ to } 0$$

$HF$ (pKa)

$$3.2$$

$COOH$ (pKa)

$$5$$

$R_2N^+H_2$ (pKa)

$$9 \text{ to } 11$$

$NH_4^+$ (pKa)

$$9.25$$

Phenol (pKa)

$$10$$

$Water/CH_3OH$ (pKa)

$$16$$

Aldehyde (pKa)

$$17$$

Ketone (pKa)

$$20$$

Ester (pKa)

$$25$$

Alkyne (pKa)

$$25 \text{ to } 26$$

$H^-$ (pKa)

$$35$$

LDA (pKa)

$$35 \text{ to } 36$$

$NH_2^-$ (pKa)

$$38$$

Benzene (pKa)

$$43 \text{ to } 44$$

Alkene (pKa)

$$44 \text{ to } 45$$

Alkane (pKa)

$$50 \text{ to } 51$$

Formal Charge Formula

Formal charge = Valence - Lone - Bond

Electronegative Trend

Increases up to the right

Atomic radius trend

Increases to down and to the left

Linear

sp, 180 degrees, 2 pi

Trigonal Planar

sp2, 120 degrees, 3 pi

Bent

sp2, 120 degrees, 2 pi 1 lone

Tetrahedral

sp3, 109.5, 4 pi

Trigonal pyramidal

sp3, 109.5 degrees, 3 pi 1 lone

Bent (again)

sp3, 109.5 degrees, 2 pi 2 lone

Polarity

Electron poor to electron rich

Prefixes

Naming ALKANES

Eclipse angle

0

Eclipse energy

High

Eclipse Stability

Low

Eclipse steric strain

High

Eclipse torsional strain

High

Staggered angle

60 (gauche) 180 (anti)

Staggered energy

mid (gauche) low (anti)

Staggered stability

mid (gauche) high (anti)

Staggered steric strain

mid (gauche) low (anti)

Staggered torsional strain

none

Alkane

Alkene

Alkyne

Aromatic Ring

Alkyl halide

Alchohol

Phenol

Ether

Amine

Aldehyde

Ketone

Carboxylic acid

More S character..

Longer bond

OENC

K value

K=10^pka(P-R) K less than 1 = more reactant

From to (resonance)

Nucleophile (ELECTRON RICH) to Electrophile (ELECTRON POOR)

ERPHEC

Alkane Stability

HBr/HI + Alkene

Break dbl bond add x to carbon H to other

HX + Alkyne xs

Break triple do rxn twice

H2/Pd/t-C

Multiple bond becomes single

H2/ Lindlar

Turn triple bond into double bond only

+H20

Break double bond, add H and OH

Degree of Unsaturation

(2C+2+N-H-X)/2