The most acidic oxide among the following is

The correct option is A

${\mathrm{N}}_2{\mathrm{O}}_5$

Explanation for correct option:

A. ${\mathrm{N}}_2{\mathrm{O}}_5$

Non-metallic oxide:

• Non-metallic oxides are formed when a non-metal reacts with oxygen gas.
• A non-metallic oxide is acidic in nature.
• General reaction for the formation of non-metallic oxide:

$\mathrm{Non}-\mathrm{metal}+\mathrm{Oxygen}\to \mathrm{Non}-\mathrm{metallic}\mathrm{oxide}$

Acidic oxides of Nitrogen:

• Dinitrogen Pentoxide is the most acidic oxide than nitrogen dioxide and Nitrogen tetraoxide as the oxides in the higher oxidation state of an element are more acidic than that of the lower oxidation state. Thus, ${\mathrm{N}}_2{\mathrm{O}}_5$ is the most acidic oxide.

Explanation for incorrect options:

B. Phosphorus lies below Nitrogen in Group-$15$. As the nature of the acidic oxide decreases down the group. Thus, ${\mathrm{P}}_2{\mathrm{O}}_5$ is less acidic oxide than ${\mathrm{N}}_2{\mathrm{O}}_5$.

C. In Nitrogen dioxide $\left({\mathrm{NO}}_2\right)$, Nitrogen exits in $+4$ oxidation state. Thus, it will be less acidic in nature than ${\mathrm{N}}_2{\mathrm{O}}_5$.

D. In Nitrogen tetraoxide $\left({\mathrm{N}}_2{\mathrm{O}}_4\right)$, Nitrogen exits in $+4$ oxidation state. Thus, it will be less acidic in nature than ${\mathrm{N}}_2{\mathrm{O}}_5$.

Hence, the correct option is A i.e. ${\mathrm{N}}_2{\mathrm{O}}_5$.