pK_a Values of Common Species in Organic Chemistry

A set of vocabulary flashcards detailing pK_a values of inorganic acids, carboxylic acids, hydrocarbons, alcohols, thiols, and the formula for calculating reaction equilibrium constants.

Reaction Equilibrium Constant ($K$)

The equilibrium constant for an acid-base reaction $HA + B \rightleftharpoons A^- + HB^+$, given by the equation $K = 10^{pK_a(HB^+) - pK_a(HA)}$.

Alkane ($R-C-H$)

A hydrocarbon species with a $pK_a$ range of $45-60$.

Alkene ($C=C-H$)

A hydrocarbon species with a $pK_a$ range of $40-50$.

Alkyne ($-C \equiv C-H$)

A hydrocarbon species with a $pK_a$ range of $23-26$.

Hydrofluoric Acid ($H-F$)

An inorganic acid with a $pK_a$ value of $3.2$.

Hydrochloric Acid ($H-Cl$)

An inorganic acid with a $pK_a$ value of $-8.0$.

Hydrobromic Acid ($H-Br$)

An inorganic acid with a $pK_a$ value of $-9.0$.

Hydroiodic Acid ($H-I$)

An inorganic acid with a $pK_a$ value of $-9.0$.

Hydrogen Cyanide ($H-CN$)

An inorganic acid with a $pK_a$ value of $9.2$.

Hydrazoic Acid ($H-N_3$)

An inorganic acid with a $pK_a$ value of $4.7$.

Water ($HO-H$)

A neutral species with a $pK_a$ value of $15.7$.

Methanol ($CH_3-O-H$)

An alcohol with a $pK_a$ value of $15.5$.

Phenol ($Ph-O-H$)

An aromatic alcohol with a $pK_a$ value of $10.0$.

Thiophenol ($Ph-S-H$)

A thiol species with a $pK_a$ value of $7.0$.

Formic Acid ($H-C(=O)-O-H$)

A carboxylic acid with a $pK_a$ value of $3.7$.

Acetic Acid ($H_3C-C(=O)-O-H$)

A carboxylic acid with a $pK_a$ value of $4.8$.

Benzoic Acid ($Ph-C(=O)-O-H$)

An aromatic carboxylic acid with a $pK_a$ value of $4.2$.