Which one of the following compounds on reaction with `Na_(2)O_(3)` in alkaline medium gives yellow colour solution?

Options

A. `Cr(OH)_(3)`
B. `Zn(OH)_(2)`
C. `Al(OH)_(3)`
D. none of these

Answer

To solve the question of which compound reacts with Na₂O₃ in an alkaline medium to give a yellow color solution, we can follow these steps:

### Step 1: Identify the Compounds
The compounds given are:
1. Cr(OH)₃ (Chromium hydroxide)
2. Zn(OH)₃ (Zinc hydroxide)
3. Al(OH)₃ (Aluminum hydroxide)
4. None of these

### Step 2: Understand the Reaction
We need to determine which of these compounds reacts with Na₂O₃ in an alkaline medium to form a yellow-colored solution. Sodium chromate (Na₂CrO₄) is known to be yellow in color.

### Step 3: Analyze Each Compound
- **Cr(OH)₃**: When chromium hydroxide reacts with Na₂O₃ in an alkaline medium, it forms sodium chromate (Na₂CrO₄), which is yellow.

- **Zn(OH)₃**: Zinc hydroxide does not produce a yellow solution when reacted with Na₂O₃. It typically forms zincate, which is not colored.

- **Al(OH)₃**: Aluminum hydroxide also does not produce a yellow solution when reacted with Na₂O₃. It forms aluminate, which is colorless.

### Step 4: Conclusion
From the analysis, we can conclude that the only compound that gives a yellow color solution upon reaction with Na₂O₃ in an alkaline medium is Cr(OH)₃.

### Final Answer
The correct option is **A: Cr(OH)₃**.

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