`Al_2O_3` was leached with alkali to get X. The solution of X on passing of gas Y, forms Z,X,Y and Z respectivily are :

Options

A. `X=NA[Al(OH)_4],Y=SO_2.Z=Al_2O_3`
B. `X=NA[Al(OH)_4],Y=CO_2,Z=Al_2O_3.xH_2O`
C. `X=[Al(OH)_3],Y=CO_2,Z=Al_2O_3`
D. `X=[Al(OH)_3],Y=SO_2,Z=Al_2O_3.XH_2O`

Answer

To solve the problem step by step, we need to identify the compounds X, Y, and Z based on the reactions described in the transcript.

### Step 1: Identify X
- **Given:** `Al2O3` (Aluminum oxide) is leached with alkali (NaOH).
- **Reaction:** Aluminum oxide is amphoteric and reacts with NaOH to form a soluble complex.
- **Result:** The reaction produces Sodium Aluminate, which is represented as:
\[ Al_2O_3 + 2NaOH + 3H_2O \rightarrow 2NaAl(OH)_4 \]
- **Conclusion:** Thus, X is Sodium Aluminate, denoted as \( NaAl(OH)_4 \).

### Step 2: Identify Y
- **Given:** The solution of X reacts with gas Y.
- **Observation:** The gas that reacts with Sodium Aluminate to form a precipitate is typically an acidic oxide.
- **Common Acidic Oxide:** Carbon dioxide (CO2) is a well-known acidic gas.
- **Reaction:** When CO2 is passed through the solution of Sodium Aluminate, it forms Aluminum Hydroxide:
\[ NaAl(OH)_4 + CO_2 \rightarrow Al(OH)_3 \downarrow + NaHCO_3 \]
- **Conclusion:** Therefore, Y is Carbon Dioxide (CO2).

### Step 3: Identify Z
- **Given:** The reaction of Y (CO2) with X (Sodium Aluminate) leads to the formation of Z.
- **Result:** The Aluminum Hydroxide formed is:
\[ Al(OH)_3 \]
- **Precipitation:** Aluminum Hydroxide can further dehydrate to form Aluminum Oxide:
\[ 2Al(OH)_3 \rightarrow Al_2O_3 + 3H_2O \]
- **Conclusion:** Thus, Z is Aluminum Oxide (Al2O3).

### Final Answer
- **X:** Sodium Aluminate (\( NaAl(OH)_4 \))
- **Y:** Carbon Dioxide (CO2)
- **Z:** Aluminum Oxide (Al2O3)

### Summary
- X = \( NaAl(OH)_4 \)
- Y = \( CO_2 \)
- Z = \( Al_2O_3 \)