Which of the following pair(s) contain species, which react with each other on mixing their aquouos solutions to give yellow precipitate?

Options

A. `NaI and NaCl`
B. `NaCl and I_(2)`
C. `AgNO_(3) and NaI`
D. `Pb(NO_(3))_(2) and NaI`

Answer

To determine which pairs of species react to form a yellow precipitate when their aqueous solutions are mixed, we can analyze each pair step by step.

### Step 1: Identify the pairs
The given pairs are:
1. Sodium iodide (NaI) and Sodium chloride (NaCl)
2. Sodium chloride (NaCl) and Iodine (I2)
3. Silver nitrate (AgNO3) and Sodium iodide (NaI)
4. Lead nitrate (Pb(NO3)2) and Sodium iodide (NaI)

### Step 2: Analyze each pair for potential reactions
1. **Sodium iodide (NaI) and Sodium chloride (NaCl)**:
- Both are soluble salts and do not react with each other to form any precipitate.
- **Result**: No yellow precipitate.

2. **Sodium chloride (NaCl) and Iodine (I2)**:
- Iodine does not react with sodium chloride in a way that would produce a precipitate.
- **Result**: No yellow precipitate.

3. **Silver nitrate (AgNO3) and Sodium iodide (NaI)**:
- When mixed, they undergo a double displacement reaction:
\[ \text{AgNO}_3 (aq) + \text{NaI} (aq) \rightarrow \text{AgI} (s) + \text{NaNO}_3 (aq) \]
- Silver iodide (AgI) is known to form a yellow precipitate.
- **Result**: Yellow precipitate forms.

4. **Lead nitrate (Pb(NO3)2) and Sodium iodide (NaI)**:
- When mixed, they also undergo a double displacement reaction:
\[ \text{Pb(NO}_3)_2 (aq) + 2\text{NaI} (aq) \rightarrow \text{PbI}_2 (s) + 2\text{NaNO}_3 (aq) \]
- Lead iodide (PbI2) is also known to form a yellow precipitate.
- **Result**: Yellow precipitate forms.

### Step 3: Conclusion
From the analysis, the pairs that produce a yellow precipitate when their aqueous solutions are mixed are:
- Pair 3: Silver nitrate and Sodium iodide
- Pair 4: Lead nitrate and Sodium iodide

### Final Answer
The pairs that contain species which react with each other to give a yellow precipitate are:
- Silver nitrate (AgNO3) and Sodium iodide (NaI)
- Lead nitrate (Pb(NO3)2) and Sodium iodide (NaI)