Question

explain tje reason the following reactions to proceed differently pb3O4 + 8 HCl - 3PbCl2 + Cl2 + 4 H2O and Pb3O4 + 4HNO3 - 2Pb(NO3)2 + PbO2 + 2H2O for 5 marks question​

Answer 1

Explanation:

Pb3O4 is actually a stoichiometric mixture of 2 moles of PbO and one mole of PbO2, i.e., 2PbO. PbO2. In PbO2, lead is present in + 4 oxidation state, whereas in PbO, lead is present in +2 oxidation state. Since +2 oxidation state or Pb is more stable, therefore, PbO2 acts as an oxidant (oxidizing agent) and hence oxidises OF ions of HCl into Cl2. Further more, PbO is a basic oxide and hence reacts with HCl to form PbCl2 and H2O. Thus the reaction of Pb2O4 with HCl can be split into two , reactions, namely, acid-base and redox reaction as shown below: Since HNO3 is an oxidizing agent, it does not react with PbO2 which is also an oxidizing agent. Therefore, no redox reaction occurs between PbO2 and HNO3. However, acid-base reaction between PbO and HNO3 occurs as follows: 2PbO + 4HNO3 → 2Pb(NO3)2 + 2H2O The overall reaction of PbO3 with HNO3 can then be written as 2PbO + PbO2 + 4HNO3 → 2Pb(NO3)2 + PbO2 + 2H2O or Pb3O4 + 4HNO3 → 2Pb(NO3)2 + PbO2 + 2H2O Thus, it is the passive nature of PbO2 against HNO3 that makes the reaction of Pb3O4 with HNO3 different from that with HCl.Read more on Sarthaks.com - https://www.sarthaks.com/608994/following-reactions-proceed-differently-pb3o4-8hcl-3pbcl2-4h2o-and-pb3o4-4hno3-pbo2-4h2o