Reaction:
(a) H2 + Cl2 → 2HCl
Explanation:
Two elements H2 and Cl2 combine to form a single compound, HCl. Hence, it is a combination reaction. As two elements combine to form a compound, it is an element – element combination.
(b) CaO + H2O → Ca(OH)2
Explanation:
Two compound CaO and HaO combine to form a single compound, Ca (OH)2. Hence, it is a combination reaction. As two compounds combine to form a new compound, it is a compound – compound combination.
(c) CaCO2 → CaO + CO2
Explanation:
The compound CaCO3 splits (decompose) into two compounds, CaO and
COO. Hence, it is a compound-com¬pound combination.
(d) FeSO4 + Mg → MgSO4 + Fe
Explanation:
Here magnesium (Mg) is displacing, iron (Fe) from its salt solution (FeSO4). Hence, it is a displacement reaction.
(e) 2KI + Pb (NO3)2 → 2KNO3 + Pbl2
Explanation:
The reactants potassium iodide and lead nitrate react to form potassium nitrate and lead iodide. From this it is clear that, radicals are intercharged by the decomposition of reactants. Hence, it is a double decomposition reaction.