Which set gives yellow ppt.?

Options

A. `KO_(3),Sb_(2)S_(3),CdS`
B. `Sb_(2)S_(3),CdS,PbCrO_(4)`
C. `PbCrO_(4),As_(2)S_(3),SnS_(2)`
D. `SnS_(2),As_(2)S_(3),PbCrO_(4),PbO`

Answer

To determine which set gives a yellow precipitate (ppt), we will analyze the compounds in each set based on their known colors when they precipitate.

### Step-by-Step Solution:

1. **Identify the Compounds in Each Set:**
- **Set 1:** K2O, Sb2S3, CdS
- **Set 2:** Sb2S3, CdS, PbCrO4
- **Set 3:** PbCrO4, As2S3, SnS
- **Set 4:** SnS, As2S3, PbO

2. **Determine the Colors of Precipitates:**
- **K2O:** Not relevant for ppt color.
- **Sb2S3 (Antimony Sulfide):** Orange ppt.
- **CdS (Cadmium Sulfide):** Yellow ppt.
- **PbCrO4 (Lead Chromate):** Yellow ppt.
- **As2S3 (Arsenic Sulfide):** Yellow ppt.
- **SnS (Tin Sulfide):** Yellow ppt.
- **PbO (Lead Oxide):** Usually red or orange color.

3. **Analyze Each Set for Yellow Precipitates:**
- **Set 1:** Contains CdS (yellow) but also Sb2S3 (orange), so does not give a yellow ppt.
- **Set 2:** Contains CdS (yellow) and PbCrO4 (yellow), but also Sb2S3 (orange), so does not give a yellow ppt.
- **Set 3:** Contains PbCrO4 (yellow), As2S3 (yellow), and SnS (yellow). All three give yellow ppt.
- **Set 4:** Contains SnS (yellow) and As2S3 (yellow), but PbO (red/orange) does not contribute to yellow ppt.

4. **Conclusion:**
- The only set that contains all compounds that give yellow ppt is **Set 3**: PbCrO4, As2S3, and SnS.

### Final Answer:
The set that gives a yellow precipitate is **Set 3**: PbCrO4, As2S3, and SnS.

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