When a manganous salt is fused with a mixture of KNO3 and NaOH the oxidation no. Of Mn changes from +2 to what?

To determine the oxidation number of Mn after the reaction, we need to understand how the oxidation state can change during a chemical reaction.

In this case, a manganous salt (Mn2+) is being fused with a mixture of potassium nitrate (KNO3) and sodium hydroxide (NaOH). During the reaction, Mn2+ can undergo oxidation, meaning it loses electrons, and its oxidation state changes.

Let's break down the reactants and products in this reaction:
- Manganous salt: Mn2+ (oxidation state: +2)
- Potassium nitrate: KNO3 (oxidation state of K: +1, oxidation state of N: +5, oxidation state of O: -2)
- Sodium hydroxide: NaOH (oxidation state of Na: +1, oxidation state of O: -2, oxidation state of H: +1)

When Mn2+ reacts with KNO3 and NaOH, the following redox reaction takes place:
2Mn2+ + 4OH- + 2KNO3 → 2KMnO4 + N2O + 2H2O

In the product, we can see that Mn2+ has changed its oxidation state to +7. Hence, the oxidation number of Mn changes from +2 to +7 in this reaction.

It changes to H2MnO4 ..oxidation no change from +2 to +6