Page 95 - Analytical Chemistry I E-book
P. 95
Solvents for Non-Aqueous Titrations
They are classified into 4 groups:
• Amphiprotic solvents: They possess both acidic and basic properties and
undergo self-ionization or autoprotolysis to yield an acid and a base. Although
water is the most common amphiprotic solvent, many other substances exhibit
similar behavior. Examples: acetic acid, methanol and ethanol.
2 CH3COOH CH3COOH + + CH3COO–
C2H5OH +2 + C2H5O–
2 C2H5OH 2
• Protophilic solvents: They are basic in nature and have high affinity for H+
ions. Examples: pyridine, dimethylformamide (DMF), and amines
(Ethylenediamine and butylamine).
• Protogenic solvents: They are acidic in nature and donate H+ ions.
Examples: sulfuric acid.
• Aprotic solvents: They are neutral and do not undergo reactions with acids
or bases, however, they are frequently added to dissolve the reactants.
Examples: chloroform (CHCl3), carbon tetrachloride (CCl4) and benzene
(C6H6).
