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 of the given reduction processes are correct, we will analyze each process based on the ability of carbon to reduce the corresponding metal oxide.

### Step-by-Step Solution:

1. **Process I: Fe₂O₃ + C → Fe**
- In this process, iron(III) oxide (Fe₂O₃) is being reduced by carbon (C) to produce iron (Fe).
- According to the Ellingham diagram, carbon can reduce iron oxides because the curve for iron lies above that of carbon. Thus, this process is **correct**.

2. **Process II: Al₂O₃ + C → Al**
- Here, aluminum oxide (Al₂O₃) is being reduced by carbon to produce aluminum (Al).
- However, the Ellingham diagram shows that aluminum is more stable than carbon, meaning carbon cannot reduce aluminum oxide. Thus, this process is **incorrect**.

3. **Process III: PbO + C → Pb**
- In this case, lead(II) oxide (PbO) is reduced by carbon to produce lead (Pb).
- The Ellingham diagram indicates that carbon can reduce lead oxide since the curve for lead lies above that of carbon. Therefore, this process is **correct**.

4. **Process IV: Ca₃(PO₄)₂ + C + SiO₂ → P**
- This process involves the reduction of calcium phosphate (Ca₃(PO₄)₂) in the presence of carbon and silica (SiO₂) to produce phosphorus (P).
- The presence of silica allows carbon to effectively reduce calcium phosphate to phosphorus. Thus, this process is **correct**.

### Conclusion:
The correct processes are:
- Process I: Fe₂O₃ + C → Fe (Correct)
- Process II: Al₂O₃ + C → Al (Incorrect)
- Process III: PbO + C → Pb (Correct)
- Process IV: Ca₃(PO₄)₂ + C + SiO₂ → P (Correct)

Therefore, the correct processes are **I, III, and IV**.

### Final Answer:
The correct processes are **I, III, and IV**.

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