Question

Which is the most acidic metal oxide and why? P2O5, As2O5, N2O5.

Answer 1

Most acidic oxide is N₂O₅,  

Explanation: these three elements belong to same group in the periodic table at the top Nitrogen is present, then P then As, as we move down then group metallic character increase thus acidic character decrease down the group.

Metals tend to be basic rather than acidic. This happens because down the group electron get away from the nucleus which make removal of electron easier, hence metallic character increases down the group. So acidic characters decrease, therefore, N₂O₅ will be the most acidic.