Physical properties of Lead
- Lead is a bluish grey metal with a bright luster.
- It is soft and can be cut with a knife and drawn into a wire and rolled into a sheet.
- It is not a good conductor of heat and electricity.
- It marks paper.
Chemical properties of Lead
a. Action of air
(i) It is unaffected by dry air but in moist air a layer of lead carbonate or lead hydroxide is deposited on its surface which protects it from further action of air.
(ii) When heated in air or oxygen, lead is oxidized to litharge (PbO) and red lead (Pb3O4)
- 2Pb + O2 → 2PbO
- 3Pb + 2O2 → Pb3O4
b. Action of water
Lead is not attacked by pure water in the absence of air, but water containing dissolved air has a solvent action on it due to the formation of lead hydroxide (a poisonous substance). This phenomenon is called Plumbo solvency.
2Pb + O2 + 2H2O → 2Pb(OH)2
c. Action of acids
- Dilute H2SO4 and HCl have no action on lead.
- Hot Conc. H2 SO4 liberates SO2 but the reaction is retarded by the formation of an insoluble layer of lead sulphate.
Pb + 2H2 SO4 → PbSO4 + 2H2O + SO2↑