Question
Question: Given, \(Pb{{O}_{2}}\) is obtained from (A)- the reaction of PbO and HCl (B)- thermal decomposi...
Given, PbO2 is obtained from
(A)- the reaction of PbO and HCl
(B)- thermal decomposition of Pb(NO3)2 at 200 oC
(C)- the reaction of Pb3O4 with HNO3
(D)- the reaction of Pb with air at room temperature
Solution
PbO2 is known as lead dioxide or plumbic oxide. It is insoluble in water and alcohol. It is a dark brown crystalline powder. The oxidation state of PbO2 is +4. It is also called as anhydrous plumbic acid.
Complete answer:
Lead (IV) oxide (PbO2) is generally obtained commercially by the reaction of lead oxide (P3O4) with dilute nitric acid (HNO3). The chemical reaction involved is given below:
Pb3O4+4HNO3→PbO2+2Pb(NO3)2+2H2O
Therefore, the correct answer will be option (C).
Let us see why the other options are correct one by one.
Reaction of PbO with HCl
Lead (II) oxide (PbO) reaction with hydrochloric acid (HCl) to form lead (II) chloride (PbCl2). The chemical reaction is given as follows:
PbO+2HCl→PbCl2+H2O
Thermal decomposition of Pb(NO3)2
Heating crystals of lead nitrate (Pb(NO3)2 ) at 200oC forms yellow coloured crystals of lead (II) oxide (PbO) , brown vapour of nitrogen dioxide (NO2) and oxygen gas. The chemical equation representing above reaction is:
2Pb(NO3)2→2PbO+4NO2+O2
Reaction of Pb with air
Lead at room temperature does not react with air. This is due to the fact that lead is coated by a layer of PbO. However, if it is heated above 600-800oC in air, it reacts with oxygen present in air to form lead (II) oxide (PbO).
Additional information:
Lead (IV) oxide shows decomposition reaction on heating. It decomposes to lead (II) oxide by the following intermediates:
PbO2→Pb12O19→Pb12O17→Pb3O4→PbO
PbO2 is an amphoteric oxide, thus, dissolves in both acids and bases. It is a powerful oxidizing agent. It is used in making matches and explosives. It is also used as an anode in electrochemical cells, in electroplating of copper, in lead storage batteries, etc.
Note: Lead forms a number of oxides in different oxidation states. Lead (II, IV) oxides are the most common oxides of lead. Do not get confused between options (B) and (C). Lead nitrate is formed during the production of PbO2 by the reaction of Pb3O4 with HNO3, it does not give PbO2.