When `HNO_(3)` is converted into `NH_(3)`, the equivalent weight of `HNO_(3)` will be:

Options

A. M/2
B. M/1
C. M/6
D. M/8

Answer

To find the equivalent weight of HNO₃ when it is converted into NH₃, we will follow these steps:

### Step 1: Determine the oxidation states of nitrogen in HNO₃ and NH₃.

- In HNO₃ (Nitric acid), nitrogen (N) has an oxidation state of +5.
- Calculation:
- Hydrogen (H) = +1
- Oxygen (O) = -2 (there are 3 O atoms, so -2 × 3 = -6)
- The overall charge of the molecule is neutral (0).
- Therefore, +1 + X - 6 = 0, which gives us X = +5.

- In NH₃ (Ammonia), nitrogen has an oxidation state of -3.
- Calculation:
- Hydrogen (H) = +1 (there are 3 H atoms, so +1 × 3 = +3)
- The overall charge of the molecule is neutral (0).
- Therefore, Y + 3 = 0, which gives us Y = -3.

### Step 2: Calculate the change in oxidation state.

- The change in oxidation state (n-factor) is calculated as follows:
- Change = Final oxidation state - Initial oxidation state
- Change = (-3) - (+5) = -3 - 5 = -8
- Since we consider the absolute change, we take n-factor as 8.

### Step 3: Calculate the molecular weight of HNO₃.

- The molecular weight of HNO₃ can be calculated as:
- H = 1 g/mol
- N = 14 g/mol
- O = 16 g/mol (there are 3 O atoms, so 16 × 3 = 48 g/mol)
- Molecular weight of HNO₃ = 1 + 14 + 48 = 63 g/mol.

### Step 4: Calculate the equivalent weight of HNO₃.

- The formula for equivalent weight is:
\[ \text{Equivalent weight} = \frac{\text{Molecular weight}}{\text{n-factor}} \]
- Substituting the values:
\[ \text{Equivalent weight of HNO₃} = \frac{63 \text{ g/mol}}{8} = 7.875 \text{ g/equiv} \]

### Conclusion

Thus, the equivalent weight of HNO₃ when converted into NH₃ is 7.875 g/equiv.