pKa Values and Organic Functional Groups

Vocabulary flashcards covering selected pKa values, acid strength trends, and organic functional groups along with their general structures and specific examples.

Table 2.1 Selected $pK_a$ Values

A reference table displaying selected acidities ($pK_a$ values) and corresponding conjugate base basicities across various molecular structures.

Organic Functional Groups Reference (Part 1)

A table listing hydrocarbons, alcohols, ethers, carbonyl compounds, and related functional groups with their general structures and specific examples.

Organic Functional Groups Reference (Part 2)

A table listing carboxylic acid derivatives, amines, ammonium ions, boranes, nitroalkanes, nitriles, imines, and enamines with their general structures and specific examples.

Alkane

A hydrocarbon with the general structure $R-H$, with propane ($CH_3CH_2CH_3$) as a specific example.

Alkene

A hydrocarbon with the general structure $R-CH=CH-R$, with 1-butene as a specific example.

Alkyne

A hydrocarbon with the general structure $R-C \equiv C-R$, with 2-butyne ($H_3C-C \equiv C-CH_3$) as a specific example.

Aromatic

A hydrocarbon functional group characterized by a benzene ring structure, with benzene as a specific example.

Phenol

A functional group with the structure $Ar-OH$ (where $Ar$ represents an aromatic group).

Alkyl Halides

Functional groups with the general structure $R-X$ (where $X = F, Cl, Br, I$), with 2-bromobutane as a specific example.

Alcohols

Functional groups with the general structure $R-OH$, with ethanol as a specific example.

Thiols

Functional groups with the general structure $R-SH$, with ethanethiol as a specific example.

Ethers

Functional groups with the general structure $R-O-R$, with diethyl ether ($H_3C-O-CH_3$) as a specific example.

Epoxides

Three-membered cyclic ether functional groups, with 1,2-epoxycyclopentane as a specific example.

Sulfide (or Thioether)

A functional group with the general structure $R-S-R$, with dimethyl sulfide ($H_3C-S-CH_3$) as a specific example.

Ketones

Functional groups with the general structure $R-(C=O)-R$, with acetone ($H_3C-(C=O)-CH_3$) as a specific example.

Aldehydes

Functional groups with the general structure $R-(C=O)-H$, with butanal as a specific example.

Carboxylic Acids

Functional groups with the general structure $R-(C=O)-OH$, with acetic acid ($H_3C-(C=O)-OH$) as a specific example.

Esters

Carboxylic acid derivatives with the general structure $R-(C=O)-O-R$, with ethyl acetate as a specific example.

Amides

Carboxylic acid derivatives with a carbonyl attached to a nitrogen (where nitrogen substituents can be $H$ or $R$ carbon groups), with N,N-dimethylformamide (DMF) as a specific example.

Acyl Halide (or Acid Halide)

Carboxylic acid derivatives with the general structure $R-(C=O)-X$ (where $X = F, Cl, Br, I$), with ethanoyl chloride as a specific example.

Acid Anhydride (or Anhydride)

Carboxylic acid derivatives with the general structure $R-(C=O)-O-(C=O)-R$, with ethanoic anhydride as a specific example.

Primary ($1^\circ$) Amine

An amine with the general structure $R-NH_2$, with ethylamine as a specific example.

Secondary ($2^\circ$) Amine

An amine with two $R$ groups attached to nitrogen ($R_2-NH$), with diethylamine as a specific example.

Tertiary ($3^\circ$) Amine

An amine with three $R$ groups attached to nitrogen ($R_3-N$), with triethylamine as a specific example.

Ammonium Ions

Positively charged nitrogen compounds with four attached groups ($R_4-N^+$ where $R$ can be $C$ or $H$), with tetramethylammonium chloride as a specific example.

Boranes

Boron compounds with the general structure $R_3-B$ (where $R$ can be $C$ or $H$), with methylborane ($H_3C-BH_2$) as a specific example.

Nitroalkanes

Functional groups with the general structure $R-NO_2$, with nitromethane as a specific example.

Nitriles

Functional groups with the general structure $R-C \equiv N$, with acetonitrile ($H_3C-C \equiv N$) as a specific example.

Imines

Functional groups containing a carbon-nitrogen double bond with the general structure $R_2C=N-R$, with N-methylethanimine as a specific example.

Enamines

Functional groups consisting of an amino group connected to an alkene carbon, with the general structure $R_2N-CR=CR_2$.

Hydrochloric Acid ($H-Cl$) $pK_a$

$H-Cl$ has a $pK_a$ of $-7$ and forms the conjugate base $Cl^-$; it is the strongest acid listed in Table 2.1.

Acetic Acid ($CH_3COOH$) $pK_a$

$CH_3COO-H$ has a $pK_a$ of $4.8$ and forms the conjugate base $CH_3COO^-$ (acetate).

Water ($HO-H$) $pK_a$

$HO-H$ has a $pK_a$ of $15.7$ and forms the conjugate base $HO^-$ (hydroxide).

Ethanol ($CH_3CH_2O-H$) $pK_a$

$CH_3CH_2O-H$ has a $pK_a$ of $16$ and forms the conjugate base $CH_3CH_2O^-$ (ethoxide).

Acetylene ($HC \equiv CH$) $pK_a$

$HC \equiv CH$ has a $pK_a$ of $25$ and forms the conjugate base $HC \equiv C^-$ (acetylide).

Hydrogen Gas ($H-H$) $pK_a$

$H-H$ has a $pK_a$ of $35$ and forms the conjugate base $H^-$ (hydride).

Ammonia ($H_2N-H$) $pK_a$

$H_2N-H$ has a $pK_a$ of $38$ and forms the conjugate base $H_2N^-$ (amide ion).

Ethylene ($CH_2=CH_2$) $pK_a$

$CH_2=CH_2$ has a $pK_a$ of $44$ and forms the conjugate base $CH_2=\bar{C}H$.

Methane ($CH_3-H$) $pK_a$

$CH_3-H$ has a $pK_a$ of $50$ and forms the conjugate base $CH_3^-$; it is the weakest acid listed in Table 2.1.