Which of the following reactions is not involved in serpeck's process of leaching of `Al_2O_3` from white bauxite ore ?

Options

A. `Al_2O_3+N_2+3Coverset(Delta)rarr2AlN+3CO`
B. `SiO_2+Coverset(Delta)rarrSi+2CO`
C. `Na_2CO_3+Al_2O_3overset(Delta)rarr2NaAlO_2+CO_2`
D. `2Al(OH)_3overset(Delta)rarrAl_2O_3+3H_2O`

Answer

To determine which reaction is not involved in Serpeck's process of leaching of Al2O3 from white bauxite ore, we will analyze the reactions involved in the process.

### Step-by-Step Solution:

1. **Understanding White Bauxite Ore**:
- White bauxite ore primarily consists of Al2O3 (alumina) and contains silica (SiO2) as an impurity.

2. **Overview of the Serpeck Process**:
- The Serpeck process is used to extract aluminum from bauxite ore. It involves several key reactions.

3. **First Reaction**:
- The powdered bauxite is mixed with carbon and heated in the presence of nitrogen. This reaction produces aluminum nitride (AlN).
- Reaction:
\[ Al_2O_3 \cdot 2H_2O + C + N_2 \rightarrow AlN + 3CO + 2H_2O \]

4. **Second Reaction**:
- Aluminum nitride is hydrolyzed with water to form aluminum hydroxide (Al(OH)3).
- Reaction:
\[ AlN + 6H_2O \rightarrow 2NH_3 + Al(OH)_3 \]

5. **Third Reaction**:
- Aluminum hydroxide is then washed, filtered, and heated to yield alumina (Al2O3).
- Reaction:
\[ Al(OH)_3 \rightarrow Al_2O_3 + H_2O \]

6. **Fourth Reaction**:
- Silica (SiO2) reacts with carbon to form silicon (Si) and carbon monoxide (CO). This reaction helps in removing silica as a volatile product.
- Reaction:
\[ SiO_2 + C \rightarrow Si + 2O \]

7. **Identifying the Reaction Not Involved**:
- The question asks which of the following reactions is not part of the Serpeck process. The reactions involving aluminum nitride, aluminum hydroxide, and silica are all part of the process.
- However, the reaction involving sodium carbonate (Na2CO3) and aluminum oxide (Al2O3) is not part of the Serpeck process.

### Conclusion:
The reaction that is not involved in the Serpeck process is:
\[ Na_2CO_3 + Al_2O_3 \text{ (This reaction does not occur in the Serpeck process)} \]