Give Reaction :
1 ) Concentrated Nitric acid oxidises red lead into lead dioxide.
2) orthoboric acid from mineral colemanite .

Answer

### Step-by-Step Text Solution

**1. Reaction of Concentrated Nitric Acid with Red Lead:**

- **Identify the reactants and products:**
- Red lead is represented by the chemical formula \( \text{Pb}_3\text{O}_4 \).
- Concentrated nitric acid is represented by \( \text{HNO}_3 \).
- The products of the reaction are lead nitrate \( \text{Pb(NO}_3\text{)}_2 \), lead dioxide \( \text{PbO}_2 \), and water \( \text{H}_2\text{O} \).

- **Write the unbalanced chemical equation:**
\[ \text{Pb}_3\text{O}_4 + \text{HNO}_3 \rightarrow \text{Pb(NO}_3\text{)}_2 + \text{PbO}_2 + \text{H}_2\text{O} \]

- **Balance the equation:**
- The balanced equation is:
\[ \text{Pb}_3\text{O}_4 + 4 \text{HNO}_3 \rightarrow 2 \text{Pb(NO}_3\text{)}_2 + \text{PbO}_2 + 2 \text{H}_2\text{O} \]

**2. Formation of Orthoboric Acid from Colemanite:**

- **Identify the reactants and products:**
- Colemanite is represented by the formula \( \text{Ca}_2\text{B}_6\text{O}_{11} \).
- The reactant for the reaction is sulfur dioxide \( \text{SO}_2 \) and water \( \text{H}_2\text{O} \).
- The products are orthoboric acid \( \text{H}_3\text{BO}_3 \) and calcium sulfite \( \text{CaSO}_3 \).

- **Write the unbalanced chemical equation:**
\[ \text{Ca}_2\text{B}_6\text{O}_{11} + \text{SO}_2 + \text{H}_2\text{O} \rightarrow \text{H}_3\text{BO}_3 + \text{CaSO}_3 \]

- **Balance the equation:**
- The balanced equation is:
\[ \text{Ca}_2\text{B}_6\text{O}_{11} + 2 \text{SO}_2 + 9 \text{H}_2\text{O} \rightarrow 6 \text{H}_3\text{BO}_3 + 2 \text{CaSO}_3 \]

### Final Balanced Reactions

1. **For the oxidation of red lead:**
\[ \text{Pb}_3\text{O}_4 + 4 \text{HNO}_3 \rightarrow 2 \text{Pb(NO}_3\text{)}_2 + \text{PbO}_2 + 2 \text{H}_2\text{O} \]

2. **For the formation of orthoboric acid:**
\[ \text{Ca}_2\text{B}_6\text{O}_{11} + 2 \text{SO}_2 + 9 \text{H}_2\text{O} \rightarrow 6 \text{H}_3\text{BO}_3 + 2 \text{CaSO}_3 \]