Answer to Question #153330 in Inorganic Chemistry for Harri

Question

Explain the following observations

(i) 𝐶𝐶𝑙4 is stable to heat while 𝑃𝑏𝐶𝑙4 readily decomposes when heated

(ii) Carbondioxide is a gas while silicon dioxide is a solid

Answer 1

Due to inert pair effect the lower membered of group 14 +4 oxidation state is unstable and readily convert to +2 oxidation state. For CCl4 +4 oxidation state is very stable but for Pb +4 oxidation state is very unstable and readily goes to Pb+2 oxidation state.

CO2 has lower molar mass than Sio2 that's why it has lower vanderwalls force of attraction. Sio2 is present as a macro molecular solid as si does not form pi bond with O atom rather it form single bond with O atom form a macro molecular solid.

Sio2 present as tetrahedral network structure to break the bond si-o is very difficult than the c=O bond. Thats why sio2 is solid but CO2 is gas