The correct decreasing order of acidic strength of trioxides of nitrogen family is

A. \(P_2O_3\)

B. \(N_2O_3\)

C. \(As_2O_3\)

D. \(Bi_2O_3\)

E. \(Sb_2O_3\)

Choose the correct answer from the options given below:

B > A > C > E > D

The correct answer is option 1. B > A > C > E > D.

Let us break down why the order of acidity for the trioxides of the nitrogen family is as follows: \(N_2O_3\) > \(P_2O_3\) > \(As_2O_3\) > \(Sb_2O_3\) > \(Bi_2O_3\).

B. Nitrogen Trioxide (\(N_2O_3\))

\(N_2O_3\) forms nitrous acid (\(HNO_2\)), which is a relatively strong weak acid. Nitrogen, being highly electronegative and having a high oxidation state in \(N_2O_3\), leads to a strong tendency to form acidic oxides. The high oxidation state of nitrogen makes \(N_2O_3\) more acidic compared to the other oxides.

A. Phosphorus Trioxide (\(P_2O_3\))

\(P_2O_3\) forms phosphorous acid (\(H_3PO_3\)). Phosphorus is less electronegative than nitrogen and is in a lower oxidation state in \(P_2O_3\) (phosphorus is +3 oxidation state here), which makes the oxide less acidic than \(N_2O_3\). While phosphorous acid is still acidic, it's weaker compared to nitrous acid.

C. Arsenic Trioxide (\(As_2O_3\))

\(As_2O_3\) forms arsenous acid (\(H_3AsO_3\)). Arsenic is in the +3 oxidation state in \(As_2O_3\), and while it is more acidic than antimony and bismuth oxides, it is less acidic than the oxides of nitrogen and phosphorus. The larger size of arsenic compared to phosphorus reduces the acidity of its oxide.

E. Antimony Trioxide (\(Sb_2O_3\))

\(Sb_2O_3\) forms antimonous acid (\(H_3SbO_3\)). Antimony is also in the +3 oxidation state here. The larger atomic size and lower electronegativity compared to arsenic result in a weaker acidic nature of its oxide.

D. Bismuth Trioxide (\(Bi_2O_3\))

\(Bi_2O_3\) forms bismuthous acid (\(H_3BiO_3\)). Bismuth is in the +3 oxidation state in \(Bi_2O_3\), but it is the least acidic among these oxides. Bismuth's large size and low electronegativity lead to the lowest acidic strength. The basic nature of \(Bi_2O_3\) is more pronounced compared to the others.

Summary of Acidity Trend:

Increasing Size and Decreasing Electronegativity: As we move down the group from nitrogen to bismuth, the size of the atoms increases, and their electronegativity decreases. This trend generally leads to a decrease in acidity. Smaller, more electronegative elements form stronger acids as their oxides are more likely to release H⁺ ions in solution.

Thus, the correct order of decreasing acidity for the trioxides is: \(N_2O_3\) > \(P_2O_3\) > \(As_2O_3\) > \(Sb_2O_3\) > \(Bi_2O_3\)