Consider the following reduction processes :
(I) `Fe_2O_3 + C rarr Fe`
(II) `Al_2O_3 + C rarr Al`
(III) `Pbo + C rarr Pb`
(IV) `Ca_3(PO_4)_2 + C + SiO_2 rarr P`
The correct processe(s) is/ are

Options

A. (I) and (III)
B. (I), (III) and (IV)
C. (II) and (III)
D. (I) and (IV)

Answer

To determine which reduction processes are correct among the given reactions, we will analyze each one step by step.

### Step 1: Analyze the first reaction
**Reaction I: `Fe2O3 + C → Fe`**

- **Oxidation States**: In `Fe2O3`, iron (Fe) has an oxidation state of +3. In elemental iron (Fe), the oxidation state is 0.
- **Reduction**: The reduction of `Fe2O3` to `Fe` means that iron is being reduced from +3 to 0, which is a reduction process.
- **Feasibility**: However, carbon (C) does not reduce `Fe2O3` directly to iron. Instead, carbon monoxide (CO) is typically used in this reduction process. Therefore, this reaction is not feasible as written.

**Conclusion**: Reaction I is incorrect.

### Step 2: Analyze the second reaction
**Reaction II: `Al2O3 + C → Al`**

- **Oxidation States**: In `Al2O3`, aluminum (Al) has an oxidation state of +3. In elemental aluminum (Al), the oxidation state is 0.
- **Reduction**: The reduction of `Al2O3` to `Al` indicates that aluminum is being reduced from +3 to 0.
- **Feasibility**: This reaction is indeed feasible and occurs in the presence of carbon, producing aluminum and carbon dioxide (CO2) as a byproduct.

**Conclusion**: Reaction II is correct.

### Step 3: Analyze the third reaction
**Reaction III: `PbO + C → Pb`**

- **Oxidation States**: In `PbO`, lead (Pb) has an oxidation state of +2. In elemental lead (Pb), the oxidation state is 0.
- **Reduction**: The reduction of `PbO` to `Pb` indicates that lead is being reduced from +2 to 0.
- **Feasibility**: This reaction is also feasible, where carbon reduces lead oxide to lead, producing carbon dioxide (CO2) as a byproduct.

**Conclusion**: Reaction III is correct.

### Step 4: Analyze the fourth reaction
**Reaction IV: `Ca3(PO4)2 + C + SiO2 → P`**

- **Products**: This reaction involves the reduction of calcium phosphate in the presence of carbon and silica (SiO2).
- **Feasibility**: The reaction produces phosphorus (P) along with slag (CaSiO3) and carbon monoxide (CO). This is a known reduction process for obtaining phosphorus from calcium phosphate.

**Conclusion**: Reaction IV is correct.

### Final Conclusion:
The correct processes are:
- Reaction II: `Al2O3 + C → Al`
- Reaction III: `PbO + C → Pb`
- Reaction IV: `Ca3(PO4)2 + C + SiO2 → P`

### Summary:
The correct processes are II, III, and IV.

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