Question

Most acidic oxide among the following is:
A. $N{O_2}$
B. ${P_2}{O_5}$
C. ${N_2}{O_4}$
D. ${N_2}{O_5}$

Answer 1

The acidic nature of the oxide depends on the position of the non-metal placed on the periodic table and the oxidation state of the non-metal present in the oxide. Greater is the oxidation state of the central atom, greater is the acidic character of the oxide.

Complete step by step answer:
The acidic oxide is defined as the oxide which on dissolving in water forms acidic solution.
The electropositive nature of the central atom determines the acidic and basic nature of the oxide. The more electropositive is the central atom of the oxide, more basic is the oxide and more electronegative is the central atom, more acidic is the oxide.
The given oxides are formed of non-metals which are electronegative in nature.
The oxidation number of the central atom also decides the acidic nature of the oxide. Higher is the oxidation number, more acidic will be the oxides.
In $N{O_2}$the oxidation state of nitrogen is +4.
In ${P_2}{O_5}$the oxidation state of phosphorus atoms is +5.
In ${N_2}{O_4}$, the oxidation state of nitrogen is +4
In ${N_2}{O_5}$, the oxidation state of nitrogen is +4.
The phosphorus atom has the highest number of oxidation states, so ${P_2}{O_5}$is most acidic in nature.
Therefore, the correct option is B.

Note:
According to the formula the oxidation state of nitrogen is +5 but according to structure the oxidation state is +4. The electropositive nature of the element increases from going left to right in the period and increases down in the column.