Acid-base behavior in solvents such as liquid ammonia follows solvent-system definitions.
Practise Acids, Bases & Electrochemistry All Acids, Bases & Electrochemistry topics
Acid-base chemistry extends to solvents other than water, where the solvent's own autoionization defines what counts as an acid or base. In a solvent-system definition, an acid increases the concentration of the solvent's cation and a base increases the concentration of its anion. In liquid ammonia, ammonium ion is the acid and amide ion is the base, and neutralization gives an ammonium salt and ammonia. These systems allow reactions that cannot occur in water, and they are important in inorganic and nonaqueous synthesis. The concept shows that acidity is not absolute.
Key ideas: Solvent-system theory: acidity depends on the solvent. Liquid NH3 autoionizes (2NH3 giving NH4+ + NH2-, pK about 33), so NH4+ is the acid and NH2- is the base; glacial acetic acid supports titration of weak bases with HClO4; DMSO and acetonitrile give very different pKa values. Alkali metals dissolve in NH3 to form blue solutions of solvated electrons.
Common mistakes and connections: Mistakes: carrying water pKa values into other solvents (pKa of acetic acid is about 12 in DMSO versus 4.76 in water), and assuming the pH scale is the same. The usable range depends on pK of autoionization. Weak bases such as amines and amides are titrated in acetic acid. Linked to the leveling effect.
Autoprotolysis constants pKs of solvents: lower pKs means a narrower acid-base range, so DMSO supports far stronger acids and bases than water. The interactive lesson shows this as a live animation or chart.
Alkali metals dissolve in liquid ammonia to give blue solutions containing solvated electrons.
Acid-base behavior in solvents such as liquid ammonia follows solvent-system definitions.
Nonaqueous Acids and Bases is a advanced topic in Acids, Bases & Electrochemistry. It builds on beginner and intermediate topics, so review those first if needed.
Study these earlier topics in Acids, Bases & Electrochemistry first: Ocean Acidification, Antacids, Leveling Effect.
The next topics in Acids, Bases & Electrochemistry are Superacids and Hard and Soft Acids and Bases.
Yes. The interactive lesson includes a self-check question on Nonaqueous Acids and Bases, and the Acids, Bases & Electrochemistry quiz draws on every topic in this area.
Nonaqueous Acids and Bases is topic 99 of 105 in Acids, Bases & Electrochemistry.