Group IVThermal decomposition of tetra chloridesCCl4 is very stable to heat.

PbCl4 is a yellow liquid which slowly decomposes at room temperature to lead (II) chloride and chlorine gas. PbCl4 decomposes rapidly on heating.PbCl4 PbCl2 + Cl2Yellow liquid white solid yellowish-green gasHydrolysis with waterCCl4 does not react with water. No low-lying d-orbital to form dative covalent bonds with H2O molecules.Furthermore, the carbon atom is the smallest atom in the group. It is bonded to four large chlorine atoms. Therefore the water molecule cannot approach the carbon atom sufficiently to start a reaction.

SiCl4 reacts with cold water:SiCl4 (l) + 4H2O(l) 4HCl(g) + SiO2 (s)White fumes and white solid/ppt GeCl4 can be hydrolysed by water to GeO2

SnCl4 and PbCl4 are only partially hydrolysed by water.

Group IV oxidesa) CO2 and SiO2 oxides are acidic oxides. They react with alkalis.CO2 (g) +2NaOH (aq) Na2CO3 (aq) + H2O (l)SiO2 (s) + NaOH (s) fused Na2SiO3 (s) + H2O (l)

b) The oxides of germanium, tin and lead are amphoteric oxides.They behave as acidic oxides-dissolving in aqueous alkalis and as basic oxides-dissolving in acids.

For e.g., lead (II) oxide dissolves in hot aqueous NaOH and in hot dilute nitric acid:PbO + 2OH- PbO2 2- + H2OPb + H+ Pb 2+ + H2O

c) Lead (IV) oxide, PbO2, does not react with nitric acid. However, it dissolves in concentrated hydrochloric acid:PbO2 + 4HCl PbCl4 + 2H2O Yellow liquidThe yellow liquid is unstable. It decomposes as shown below:PbCl4 (l) PbCl2 (s) + Cl2 (g)PbO2 (s) + 4HCl (conc.) PbCl2 (s) + Cl2 (g) + 2H2O (l)

The PbCl4 decomposes slowly at room temperature.

d) Pb3O4 is an ionic oxide made up of Pb2+, Pb4+ and O2- ions. It behaves in chemical reactions as if it is a mixture of 2PbO and PbO2. Hence with nitric acid, the PbO part dissolves while the PbO2 does not. The equation for the reaction is:Pb3O4 (s) + 4HNO3 (aq) 2Pb (NO3)2 (aq) + 2H2O (l) + PbO2 (s)red solid dark brown solid