A powdered salt (X) in a dry test tube was heated that evolves brown fumes of nitrogen dioxide and a yellow residue of lead oxide is also formed. The salt (X) is
The salt (X) is undergoing thermal decomposition reaction as it breaks to give multiple products on heating. Release of brown fumed Nitrogen dioxide (NO2) gas indicates that the salt is a nitrate salt. Moreover formation of a yellow lead oxide (PbO) residue indicates that the salt is a lead salt. Thus the salt is Lead Nitrate. The thermal decomposition reaction involved is:
2Pb(NO3)2→ 2PbO + 4NO2 + O2