Question

question 23 of 37
estimate the pkₐ values for the functional group classes represented by the given molecules.
(chemical structures of molecules and answer bank with numbers 50, 35, 10, 15, 5, 25)

Explanation:

1. Ethanol (alcohol): Alcohols have typical pKa ~15.
2. Acetic acid (carboxylic acid): Carboxylic acids have pKa ~5.
3. Ethanammonium (protonated amine): Protonated aliphatic amines have pKa ~10.
4. Isobutane (alkane): Alkanes are very weak acids, pKa ~50.
5. 3-methyl-1-butyne (terminal alkyne): Terminal alkynes have pKa ~25.
6. Diethylamine (amine, neutral): Neutral aliphatic amines have pKa ~35 (pKa of their conjugate acid is ~10, so pKa of the free amine is much higher).

Answer:

1. Ethanol: 15
2. Acetic acid: 5
3. Ethanammonium: 10
4. Isobutane: 50
5. 3-methyl-1-butyne: 25
6. Diethylamine: 35