Hello !
Combination reactions are the reactions between different substances that result in a single compound :
A + B → C
A - reactant
B - reactant
C - product (compound)
C4H12 + 7O2 ⟶ 6H2O + 4CO2 ( There are 2 compounds,so it is not a combination reaction)
2H2 + O2 ⟶ 2H2O ( There is a single compound,so it is a combination reaction)
Al2S3 ⟶ 2Al + 3S ( There are two compuns and a single reactant,so it is a
decomposition reaction)
Cl2 + 2KBr ⟶ 2KCl + Br2
( There are 2 compounds,so it is not a combination reaction)
ANSWER : 2H2 + O2 ⟶ 2H2O
