`Na_(2)SO_(3), NaCl, Na_(2)C_(2)O_(4),Na_(2)CrO_(4),NaNO_(2),CH_(3)CO_(2)Na` are separately treated with `AgNO_(3)` solution. In how many many cases is/are white ppt. obtained?

Explanation

To determine how many cases result in a white precipitate when the compounds \( \text{Na}_2\text{SO}_3, \text{NaCl}, \text{Na}_2\text{C}_2\text{O}_4, \text{Na}_2\text{CrO}_4, \text{NaNO}_2, \text{CH}_3\text{CO}_2\text{Na} \) are treated with \( \text{AgNO}_3 \) solution, we need to analyze each compound individually.

### Step 1: Analyze each compound
1. **\( \text{Na}_2\text{SO}_3 \)**:
- When treated with \( \text{AgNO}_3 \), it can form \( \text{Ag}_2\text{SO}_3 \). However, silver sulfite is not a common precipitate and is generally soluble.
- **Result**: No white precipitate.

2. **\( \text{NaCl} \)**:
- When treated with \( \text{AgNO}_3 \), it forms \( \text{AgCl} \), which is a well-known white precipitate.
- **Result**: White precipitate forms.

3. **\( \text{Na}_2\text{C}_2\text{O}_4 \)**:
- When treated with \( \text{AgNO}_3 \), it forms \( \text{Ag}_2\text{C}_2\text{O}_4 \). Silver oxalate is a white precipitate.
- **Result**: White precipitate forms.

4. **\( \text{Na}_2\text{CrO}_4 \)**:
- When treated with \( \text{AgNO}_3 \), it forms \( \text{Ag}_2\text{CrO}_4 \), which is a yellow precipitate.
- **Result**: No white precipitate.

5. **\( \text{NaNO}_2 \)**:
- When treated with \( \text{AgNO}_3 \), it forms \( \text{AgNO}_2 \), which is also soluble and does not form a precipitate.
- **Result**: No white precipitate.

6. **\( \text{CH}_3\text{CO}_2\text{Na} \)**:
- When treated with \( \text{AgNO}_3 \), it forms \( \text{AgCH}_3\text{COO} \), which is generally soluble and does not form a precipitate.
- **Result**: No white precipitate.

### Step 2: Summary of results
- **Compounds that form white precipitate**:
- \( \text{NaCl} \) (forms \( \text{AgCl} \))
- \( \text{Na}_2\text{C}_2\text{O}_4 \) (forms \( \text{Ag}_2\text{C}_2\text{O}_4 \))

### Final Answer
In total, white precipitates are obtained in **2 cases**: from \( \text{NaCl} \) and \( \text{Na}_2\text{C}_2\text{O}_4 \).

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