MnO2 + KMnO4 + H2O=

The reaction between manganese dioxide (MnO₂), potassium permanganate (KMnO₄), and water (H₂O) typically occurs in acidic conditions and can produce manganese(II) ions (Mn²⁺) and potassium ions (K⁺) among other possible products depending on the specific conditions and concentrations.

In acidic conditions, the overall balanced chemical reaction may look like this:

\[ 2 KMnO4 + 3 H2SO4 + 5 MnO2 \rightarrow 5 MnSO4 + K2SO4 + 3 H2O + 2 O2 \]

This reaction generally highlights the reduction of permanganate and the oxidation state changes of manganese. Please ensure to confirm the specific conditions (e.g., presence of acids, concentrations, etc.) as they can affect the products and the stoichiometry of the reaction.