Which of the following compounds decomposes to produce litharge (PbO)?

Litharge (PbO) is the monoxide of lead, a yellow to reddish crystalline compound that represents the most stable oxide form of lead at elevated temperatures. Several other oxides of lead, such as Pb₂O (lead suboxide), Pb₃O₄ (red lead or minium), and PbO₂ (lead dioxide), decompose upon heating to yield PbO as the final product.

Let’s examine the thermal behavior of each oxide:

1. 
   

   Lead suboxide (Pb₂O):
   It is an unstable compound that decomposes readily on heating:
   Pb₂O → 2PbO

   
   


2. 
   

   Red lead (Pb₃O₄):
   Red lead is an intermediate oxide of lead that can be viewed as a combination of PbO and PbO₂. On heating, it decomposes into PbO and oxygen gas:
   2Pb₃O₄ → 6PbO + O₂

   
   


3. 
   

   Lead dioxide (PbO₂):
   Lead dioxide is a brown crystalline compound that decomposes upon heating to yield PbO and oxygen gas:
   2PbO₂ → 2PbO + O₂

   
   

These decomposition reactions show that all these oxides convert into litharge (PbO) when heated. PbO itself is stable up to about 880°C, beyond which it can decompose into metallic lead and oxygen under reducing conditions.

Litharge plays an important role in metallurgy, glass manufacturing, and ceramics. It is also used in making lead-based paints, storage batteries, and glazes. In redox chemistry, PbO acts as an oxidizing agent and is a product of many thermal decomposition reactions involving lead compounds.

Therefore, since Pb₂O, Pb₃O₄, and PbO₂ all yield litharge (PbO) upon heating, the correct answer is “All of the above.” This illustrates the thermodynamic stability of PbO among the oxides of lead and its significance in inorganic and industrial chemistry