Write the equation of reactions that prove the acidic nature of such oxides: SeO2, SO3, Mn2O7, P2O5, CrO3

Let us write down the reaction equations for acid oxides:
SeO2 + H2O = H2SeO3 – compound reaction;
SeO2 + 2NaOH = Na2SeO3 + H2O – ion exchange;
SeO2 + H2O2 = H2SeO4 – oxidation;
SO3 + H2O = H2SO4 – compounds;
2NaOH + SO3 = Na2SO4 + H2O – ion exchange;
SO2 + K2O = K2SO4 – compounds;
Mn2O7 + H2O = 2HMnO4 – compounds;
Mn2O7 + 2NaOH = 2NaMnO4 + H2O- exchange;
P2O5 + 3H2O = 2H3PO4 – compounds;
BaO + P2O5 = Ba (PO3) 2 – compounds;
NaOH + P2O5 = Na3PO4 + 3H2O – exchange;
2CrO3 + H2O = H2Cr2O7 – compounds;
СrO3 + 2KOH = K2CrO4 + H2O – exchange.