Complete the following chemical reactions. (i) PbS(s)+H 2 ​ O 2 ​ (aq)→ (ii) MnO 4 − ​ (aq)+H 2 ​ O 2 ​ (aq)→ (iii) CaO(s)+H 2 ​ O(g)→

Explanation

To complete the given chemical reactions, we will analyze each reaction step by step.

### (i) PbS(s) + H₂O₂(aq) →
1. **Identify Reactants**: We have lead sulfide (PbS) and hydrogen peroxide (H₂O₂).
2. **Determine Products**: Lead sulfide reacts with hydrogen peroxide to produce lead sulfate (PbSO₄) and water (H₂O).
3. **Balance the Reaction**: The balanced equation is:
\[ \text{PbS}(s) + 4 \text{H}_2\text{O}_2(aq) \rightarrow \text{PbSO}_4(s) + 4 \text{H}_2\text{O}(l) \]

### (ii) MnO₄⁻(aq) + H₂O₂(aq) →
1. **Identify Reactants**: We have permanganate ion (MnO₄⁻) and hydrogen peroxide (H₂O₂).
2. **Determine Products**: In an acidic medium, permanganate reacts with hydrogen peroxide to produce manganese ions (Mn²⁺) and oxygen gas (O₂).
3. **Balance the Reaction**: The balanced equation is:
\[ 2 \text{MnO}_4^-(aq) + 5 \text{H}_2\text{O}_2(aq) \rightarrow 2 \text{Mn}^{2+}(aq) + 5 \text{O}_2(g) + 4 \text{H}_2\text{O}(l) \]

### (iii) CaO(s) + H₂O(g) →
1. **Identify Reactants**: We have calcium oxide (CaO) and water vapor (H₂O).
2. **Determine Products**: Calcium oxide reacts with water to form calcium hydroxide (Ca(OH)₂).
3. **Balance the Reaction**: The balanced equation is:
\[ \text{CaO}(s) + \text{H}_2\text{O}(g) \rightarrow \text{Ca(OH)}_2(s) \]

### Final Balanced Reactions:
1. \( \text{PbS}(s) + 4 \text{H}_2\text{O}_2(aq) \rightarrow \text{PbSO}_4(s) + 4 \text{H}_2\text{O}(l) \)
2. \( 2 \text{MnO}_4^-(aq) + 5 \text{H}_2\text{O}_2(aq) \rightarrow 2 \text{Mn}^{2+}(aq) + 5 \text{O}_2(g) + 4 \text{H}_2\text{O}(l) \)
3. \( \text{CaO}(s) + \text{H}_2\text{O}(g) \rightarrow \text{Ca(OH)}_2(s) \)