Select the correct statement about elements of group `15^(th)`

Options

A. The order of stability of oxidation state for +3 is `Bi^(3+) gt Sb^(3+) gt As^(3+)` and for `+5` is `Bi^(5+)lt Sb^(5+) lt As^(5+)`
B. In case of nitrogen , all oxidation state from +1 to +4 tend to disproportionate in acid solution
C. There is a considerable increase in covalent radius from N to P but from As to Bi only a small increase in covalent radius is observed
D. All of these

Explanation

To solve the question regarding the correct statements about the elements of group 15, we will analyze each statement step by step.

### Step 1: Understanding Group 15 Elements
Group 15 elements, also known as the nitrogen family, include nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). Each of these elements has distinct properties and oxidation states.

### Step 2: Analyzing Statement A
**Statement A**: The order of stability of the oxidation state +3 is Bi^3+ > Sb^3+ > As^3+, and that of +5 is Bi^5+ > Sb^5+ > As^5+.

- **Explanation**: As we move down the group, the stability of the +5 oxidation state decreases while the stability of the +3 oxidation state increases due to the inert pair effect. The inert pair effect refers to the tendency of the s-electrons in the outermost shell to remain paired and not participate in bonding, leading to greater stability in the +3 state for heavier elements like bismuth.

### Step 3: Analyzing Statement B
**Statement B**: In the case of nitrogen, oxidation states from +1 to +4 tend to disproportionate in acidic solution.

- **Explanation**: This statement is correct. For example, in nitrous acid (HNO2), nitrogen in the +3 oxidation state can disproportionate into nitrogen in the +2 oxidation state (NO) and the +5 oxidation state (HNO3). This reaction involves both oxidation and reduction, which is characteristic of disproportionation.

### Step 4: Analyzing Statement C
**Statement C**: There is a considerable increase in covalent radius from nitrogen to phosphorus, but from arsenic to bismuth, only a small increase in covalent radius is observed.

- **Explanation**: This statement is also correct. The increase in covalent radius from nitrogen to phosphorus is due to the increase in the principal quantum number. However, from arsenic to bismuth, the increase is minimal due to the presence of f-orbitals, which have poor shielding effect, leading to less effective nuclear charge felt by the outermost electrons.

### Step 5: Conclusion
Since all three statements (A, B, and C) are correct, the answer to the question is:

**Correct Answer**: D) All of the above.

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