Chemistry

31. Properties of Ionic Compounds :
(i) Ionic compounds are solids, e.g., NaCl, KCl, CuSO₄, K₂SO₄, NaNO₃ are solids.
(ii) Ionic compounds are somewhat hard and brittle. It is due to strong force of attraction between them.
(iii) Ionic compounds have closed packed structures, e.g., NaCl has face centred cubic structure.
(iv) Ionic compounds have high melting and boiling points. It is because of strong force of attraction between oppositely charged ions, therefore, high energy is required to break the metallic bonds between ions.
(v) Ionic or electro valent compounds are soluble in water because they form ions in aqueous solution.
(vi) Ionic compounds are insoluble in organic solvents like alcohol, acetone, ether, chloroform, carbon disulphide etc. because they do not form ions in organic solvents.
(vii) Ionic compounds conduct electricity in molten state and in aqueous solution because ions carry current. The movement of ions take place towards oppositely charged electrode in electric field.
(viii) They do not conduct electricity in solid state because ions are not free to move.
32. Conclusion :
It shows that ionic compounds conduct electricity in aqueous solution. Corrosion. It is a process in which metal reacts with substance present in atmosphere to form surface compounds, e.g., silver metal turns black due to formation of Ag₂S) Copper forms a greenish layer of CuCO₃.Cu(OH)₂ on its surface. Iron forms reddish brown coating of hydrated ferric oxide, Fe₂O₃ x H₂O