`4Mg+10HNO_(3)to4Mg(NO_(3))_(2)+NH_(4)NO_(3)+3H_(2)O`. In this reaction

Options

A. 96 gms magnesium can reduce one mole of `HNO_(3)`
B. Equivalent weight of reduced `HNO_(3)` is `1/8` of its molecular weight
C. Entire `HNO_(3)` involved in the reaction is reduced
D. `HNO_(3)` is reduced to the best possible extent

Answer

To analyze the given reaction and determine the correctness of the statements about it, we will follow a systematic approach.

### Step-by-Step Solution:

1. **Write the Balanced Reaction:**
The balanced chemical reaction is:
\[ 4 \text{Mg} + 10 \text{HNO}_3 \rightarrow 4 \text{Mg(NO}_3\text{)}_2 + \text{NH}_4\text{NO}_3 + 3 \text{H}_2\text{O} \]

2. **Determine Oxidation States:**
- In HNO₃, nitrogen (N) has an oxidation state of +5.
- In NH₄NO₃, nitrogen in the ammonium ion (NH₄⁺) has an oxidation state of -3.
- The nitrogen in the product Mg(NO₃)₂ remains +5.

3. **Identify Redox Changes:**
- The nitrogen in HNO₃ (oxidation state +5) is reduced to -3 in NH₄NO₃.
- Therefore, the nitrogen in HNO₃ is undergoing reduction.

4. **Calculate the Amount of Magnesium:**
- The molecular weight of magnesium (Mg) is 24 g/mol.
- Since 4 moles of magnesium react with 10 moles of HNO₃, we can calculate the mass of magnesium required to reduce 1 mole of HNO₃:
\[ 4 \text{ moles of Mg} = 4 \times 24 \text{ g} = 96 \text{ g} \]
Hence, 96 g of magnesium will reduce 1 mole of HNO₃.

5. **Determine Equivalent Weight of Reduced HNO₃:**
- The change in oxidation state for nitrogen in HNO₃ is from +5 to -3, which is a change of 8.
- The equivalent weight of HNO₃ can be calculated as:
\[ \text{Equivalent weight} = \frac{\text{Molecular weight}}{\text{Number of electrons transferred}} = \frac{\text{Molecular weight}}{8} \]
Thus, the equivalent weight of reduced HNO₃ is indeed 1/8 of its molecular weight.

6. **Evaluate Statements:**
- **Statement 1:** "4 moles of magnesium reduce 1 mole of HNO₃." - **Correct**
- **Statement 2:** "Equivalent weight of reduced HNO₃ is 1/8 of its molecular weight." - **Correct**
- **Statement 3:** "Entire HNO₃ involved in this reaction is reduced." - **Incorrect** (only part of it is reduced)
- **Statement 4:** "HNO₃ is reduced to the best possible extent." - **Correct** (as -3 is the lowest oxidation state for nitrogen)

### Final Conclusion:
The correct statements are 1, 2, and 4.