Of the following the most acidic is:

Key Points

• All the elements of the group 15 elements form tri oxides and pentoxides having the general formula M₂O₃ or M₂O₅.
• The oxides of Nitrogen, Phosphorus, and Arsenic are acidic.
• The trioxide of antimony Sb2O3 is amphoteric while that of bismuth Bi2O3 is basic.
• As2O3 is acidic in nature.
• The pentoxides of all these elements are acidic but acidic character decreases down the group.
• Thus, P₂O₅ is the strongest acidic oxide whereas Bi₂O₃  is the weakest acidic oxide.
• The acidic character of the same element increases with an increase in the oxidation state.

Hence, the most acidic oxide among the following is P2O5.

​Important Points

Facts about P₂O₅:

•  It is also written as P₄O₁₀ and is called phosphorus pentoxide.
• It is prepared by burning phosphorus in excess of air or oxygen. It is a white solid which sublimes on heating.
• It is a strong dehydrating agent and dehydrates nitric acid as well as sulphuric acid.
• The structure is:

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Additional Information

• N₂O₅ is the most acidic of group 15 elements.