Mg liberates `H_(2)` on reaction with

Options

A. dil.HCl
B. dil`.H_(2)SO_(4)`
C. very dil.`HNO_(3)`
D. All of these

Answer

To solve the question "Mg liberates H₂ on reaction with," we will analyze the reactions of magnesium (Mg) with different acids: dilute hydrochloric acid (HCl), dilute sulfuric acid (H₂SO₄), and very dilute nitric acid (HNO₃).

### Step-by-step Solution:

1. **Reaction with Dilute Hydrochloric Acid (HCl)**:
- When magnesium reacts with dilute hydrochloric acid, the reaction can be represented as:
\[ \text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2 \]
- In this reaction, magnesium chloride (MgCl₂) is formed, and hydrogen gas (H₂) is liberated.

2. **Reaction with Dilute Sulfuric Acid (H₂SO₄)**:
- When magnesium reacts with dilute sulfuric acid, the reaction can be represented as:
\[ \text{Mg} + \text{H}_2\text{SO}_4 \rightarrow \text{MgSO}_4 + \text{H}_2 \]
- Here, magnesium sulfate (MgSO₄) is formed, and hydrogen gas (H₂) is also released.

3. **Reaction with Very Dilute Nitric Acid (HNO₃)**:
- When magnesium reacts with very dilute nitric acid, the reaction can be represented as:
\[ \text{Mg} + 2\text{HNO}_3 \rightarrow \text{Mg(NO}_3)_2 + \text{H}_2 \]
- In this case, magnesium nitrate (Mg(NO₃)₂) is formed, and hydrogen gas (H₂) is liberated.

4. **Conclusion**:
- In all three cases (dilute HCl, dilute H₂SO₄, and very dilute HNO₃), magnesium liberates hydrogen gas. Therefore, the correct answer is that magnesium liberates hydrogen gas on reaction with all of these acids.

### Final Answer:
**Option 4: All of these.**