Which of the following statement(s) is//are incorrect ?

Options

A. `SbH_(3) gt NH_(3) gt ASH_(3) gt PH_(3)`("boiling point")
B. `H_(3)PO_(4) gt H_(3)PO_(3) gt H_(3)PO_(2)`("reducing character")
C. `N_(2)O lt NO lt N_(2)O_(3) lt N_(2)O_(5)`("oxidation state on nitrogen atom")
D. `NH_(3) gt PH_(3) gt ASH_(3) gt SbH_(3)ge BiH_(3)`("basicity")

Explanation

To solve the question "Which of the following statement(s) is/are incorrect?" regarding the properties of group 15 elements, we will analyze each statement step by step.

### Step 1: Analyze the boiling points of group 15 hydrides
- The hydrides of group 15 elements include NH3 (ammonia), PH3 (phosphine), AsH3 (arsine), and SbH3 (stibine).
- As we move down the group from nitrogen to antimony, the size of the atoms increases, leading to an increase in boiling points due to increased van der Waals forces.
- However, NH3 has a higher boiling point than PH3 and AsH3 due to hydrogen bonding, which is significant in NH3 due to its high electronegativity.
- The correct order of boiling points is: SbH3 < PH3 < AsH3 < NH3.
- Therefore, this statement is **correct**.

### Step 2: Analyze the reducing character of oxoacids of phosphorus
- The oxoacids of phosphorus include H3PO5 (phosphoric acid), H3PO3 (phosphorous acid), and H3PO2 (hypophosphorous acid).
- The oxidation states of phosphorus in these acids are +5, +3, and +1 respectively.
- As the oxidation state decreases, the reducing character increases. Thus, H3PO2 should have the highest reducing character, followed by H3PO3, and then H3PO5.
- The statement claiming the order of reducing character is incorrect because it suggests the opposite.
- Therefore, this statement is **incorrect**.

### Step 3: Analyze the oxidation states of nitrogen
- The oxidation states of nitrogen can be +1, +2, +3, and +5.
- The increasing order of oxidation states is indeed +1 < +2 < +3 < +5.
- This statement is **correct**.

### Step 4: Analyze the basicity of group 15 hydrides
- The basicity of the hydrides (NH3, PH3, AsH3, SbH3) decreases down the group.
- This is because as the size of the central atom increases, the electron density decreases, leading to a lower tendency to donate the lone pair of electrons.
- Therefore, the basicity order is indeed correct: NH3 > PH3 > AsH3 > SbH3.
- This statement is **correct**.

### Conclusion
After analyzing all the statements:
- The only incorrect statement is the one regarding the reducing character of oxoacids of phosphorus.

Thus, the answer to the question is that **only the second statement is incorrect**.