Explanation:
Chemical reaction
When two or more substances react and form some new substance it is called as chemical reaction .
There are so many reactions , out of which decomposition is also one type .
It is explained below :
Decomposition reaction
it is the type in which a reactant breaks up into its constituents either by heating or passing current or in presence of light .
That is :
(a) Photo decomposition (breaking in presence of light )
Examples AgCl-----Ag+Cl₂
(white ) (grey )
(B)Electrolytic decomposition : breaking by passing current
Example : NaCl------Na+Cl₂
©Thermal decomposition : breaking by heating )
Example : Pb(No₃)₂-----PbO+NO₂+O₂
(reddish brown gas )
ACTIVITY TO DEMONSTRATE : heating of ferrous sulphate
FeSO₄.7H2O------FeSO₄+7H₂O
(GREEN )
FeSO₄-----------------heat -------Fe₂O₃+SO₂+SO₃
This question is done considering : Identify the type of reaction
2 Pb(NO3)2 – 2 PbO + 4 NO2 + O2