Question

What reaction would be the chemical equation 2H2O->2H2+O2 represent? A.decomposition of water b. Formation of water c. Combustion of water d. Replacement of water

Answer 1

It's decomposition
A combustion reaction involves carbon dioxide so it can't be that
The water is not being formed
The water is not replaced by the other molecules
So it is decomposition, not just from process of elimination, but also because decomposing water means heating it.

Answer 2

Decomposition of water

Step-by-step explanation:

The chemical equation 2H₂O -> 2H₂ + O₂ shows two water molecules as reactants, and hydrogen and oxygen as products. This indicates that water is being broken down in this reaction. Another word for this is decomposition.

Formation of water would occur if the arrow was facing the other way (if hydrogen and oxygen were the reactants), however this is not the case, so formation would be incorrect.

Combustion reactions involve a substrate reacting with oxygen, usually producing heat.

Replacement of water is not occurring since the water molecules are being broken down.