Sum of oxidation state of nitrogen atom in hyponitrous acid, nitric acid and nitrous acid.

Explanation

To find the sum of the oxidation states of nitrogen in hyponitrous acid, nitric acid, and nitrous acid, we will calculate the oxidation state of nitrogen in each compound step by step.

### Step 1: Calculate the oxidation state of nitrogen in hyponitrous acid (N₂OH)

1. **Identify the formula**: The formula for hyponitrous acid is N₂OH.
2. **Assign oxidation states**:
- Let the oxidation state of nitrogen be \( x \).
- The hydroxyl group (OH) has an oxidation state of -1.
3. **Set up the equation**: Since there are two nitrogen atoms, the equation becomes:
\[ 2x + (-1) = 0 \]
4. **Solve for \( x \)**:
\[ 2x - 1 = 0 \implies 2x = 1 \implies x = +1 \]
5. **Conclusion**: The oxidation state of nitrogen in hyponitrous acid is +1.

### Step 2: Calculate the oxidation state of nitrogen in nitric acid (HNO₃)

1. **Identify the formula**: The formula for nitric acid is HNO₃.
2. **Assign oxidation states**:
- Let the oxidation state of nitrogen be \( x \).
- The oxidation state of hydrogen is +1 and that of oxygen is -2.
3. **Set up the equation**: The equation becomes:
\[ +1 + x + 3(-2) = 0 \]
4. **Solve for \( x \)**:
\[ 1 + x - 6 = 0 \implies x - 5 = 0 \implies x = +5 \]
5. **Conclusion**: The oxidation state of nitrogen in nitric acid is +5.

### Step 3: Calculate the oxidation state of nitrogen in nitrous acid (HNO₂)

1. **Identify the formula**: The formula for nitrous acid is HNO₂.
2. **Assign oxidation states**:
- Let the oxidation state of nitrogen be \( x \).
- The oxidation state of hydrogen is +1 and that of oxygen is -2.
3. **Set up the equation**: The equation becomes:
\[ +1 + x + 2(-2) = 0 \]
4. **Solve for \( x \)**:
\[ 1 + x - 4 = 0 \implies x - 3 = 0 \implies x = +3 \]
5. **Conclusion**: The oxidation state of nitrogen in nitrous acid is +3.

### Step 4: Sum the oxidation states

Now, we will sum the oxidation states calculated for each acid:
\[ \text{Sum} = (+1) + (+5) + (+3) = 9 \]

### Final Answer:
The sum of the oxidation states of nitrogen in hyponitrous acid, nitric acid, and nitrous acid is **9**.

---