for university students

1. Dr.Sakina.Z.Bootwala
Wilson College

2. Classification of solvents
Dr. Julekha Shaikh, Maharashtra College.

3. Protonic/ protic solvents are those which donate
protons. They are acids on the basis of Bronsted – Lowry concept. e.g.
CH3COOH, HF, H₂SO₄, H₂O etc.
H₂O  H+ + OH —
CH3COOH  H+ + CH3COO —
HF  H+ + F —
H₂SO₄  2H+ + SO₄ —2
Protonic solvents are also those which accept protons i.e. Bronsted – Lowry
base NH3 + H+  NH4
+
Non protonic /Aprotic solvents are those which neither
donate nor accept protons. e.g. C6H6, CCl4, acetonitrile, dimethyl
sulphoxide, BrF3, SO2 etc.

4. Acidic solvents are those which have strong tendency to
donate protons. e.g. H3SO4, CH3COOH, HF.
CH3COOH  H+ + CH3COO —
HF  H+ + F —
Basic solvents are those which have strong tendency to accept
protons. e.g. NH3, ethylenediamine, Pyridine, Hydrazine (NH2–NH2).
NH3 + H+  NH4
+
NH2—CH2—CH2—NH2 + 2H+  + NH3—CH2—CH2—NH3
+
Dr. Julekha Shaikh, Maharashtra College.

5. Amphiprotic solvents are those which
accepts as well as donate protons. e.g. H2O, CH3OH, ethanol.
H2O  H+ + OH— ; H2O + H+  H3O+
CH3OH  H+ + CH3O— ; CH3OH + H+  CH3OH2
+
Aprotic solvents are those which neither donate nor accept
protons. They can be further classified into:
(i) Non polar, non solvating solvents with zero dipole moment. e.g. C6H6, CCl4
etc.
(ii) Polar coordinating solvents like acetonitrile, dimethyl sulphoxide etc.
(iii) Polar autoionising solvents such as BrF3, SO2 etc.
Dr. Julekha Shaikh, Maharashtra College.

6. • Ionizing solvent are those which bring out ionisation of the solutes.
• This property of the solvents is due to their polar nature.
• They have high dipole moment and dielectric constant.
• These solvent undergo autoionisation. e.g. H2O, NH3, HF, SO2, N2O4,
HCN etc.
H2O + H2O  H3O+ + OH—
HCN + HCN  H2CN+ + CN —
Dr. Julekha Shaikh, Maharashtra College.

7. •Non-ionizing solvent are those which does not bring about ionisation of
the solutes.
•They are practically non-polar nature.
•They have low dipole moment and dielectric constant.
•the ionic solutes do not undergo ionization in such solvents.
•Covalent or non-polar solutes dissolve in these solvents.
• These solvent do not undergo autoionisation. e.g. C6H6, CCl4 etc.
Dr. Julekha Shaikh, Maharashtra College.

8. 4. Coordinating & Non-Coordinating Solvents
 The solvents which are capable of coordinating with the
metal ion or anions of the solute are coordinating Solvents.
Example: H 2O, NH3,SO2,nitro methane etc.
Cu+2 + 4NH3 → [Cu(NH3)4 ]+2
 Solvents which are not capable of coordinating with the
metal ions or anions of the solute are non- coordinating
solvents ,Example: CCl4, saturated hydrocarbons.