Final answer:
The reaction MnSO₄ → MnO + SO₃ is a decomposition reaction, where a single compound breaks down into two or more new substances. It is not a synthesis, single-displacement, double-displacement, or combustion reaction.
Step-by-step explanation:
If MnSO₄ is breaking down into MnO + SO₃, this is a type of reaction in which a single compound breaks down to form two or more new substances. This type of reaction is called a decomposition reaction. It is not a synthesis reaction, as those involve combining substances to form a single compound. Additionally, it is not a single-displacement reaction because that would involve an element being replaced in a compound by another element.
It is also not a double-displacement reaction since these require the exchange of ions between two compounds, usually resulting in a precipitate or a gas, which is not what is happening here. Lastly, it is not a combustion reaction because combustion typically involves the burning of a substance in the presence of oxygen, leading to the formation of carbon dioxide and water.