Answer to Question #60138 in Organic Chemistry for Collins

Question

Which of the following oxides are acidic: PbO, PbO2, CaO, SiO2, P2O3, P2O5

Answer 1

According to the definition - acidic oxides are oxides of nonmetals. They can also be termed as inorganic chemicals that react with water forming an acid; or react with a base forming a salt.
SiO2 does not react with water but it reacts with base and forms silicate:
SiO2 +NaOH=NaSiO3 +H2O
Phosphorus trioxide P2O3 - empiric formula, molecular formulais P4O6 reacts with cold water and forms phosphorous acid
P4O6 + 6 H2O = 4 H3PO3
Finally, phosphorus pentoxide is very active with water and forms phosphoric acid
P4O10+ 6H2O= 4H3PO4
So acidic oxides from the list above are: SiO2, P2O3, P2O5