DMG gives a rosy red crystalline ppt with

Options

A. `Zn^(2+)`
B. `Ni^(2+)`
C. `Cu^(2+)`
D. `Mn^(2+)`

Answer

To solve the question "DMG gives a rosy red crystalline ppt with", we will analyze the options provided and determine which metal ion reacts with dimethylglyoxime (DMG) to form a rosy red precipitate.

### Step-by-Step Solution:

1. **Understanding DMG**:
- DMG stands for dimethylglyoxime, which is a reagent used to detect certain metal ions, particularly nickel (Ni²⁺).

2. **Identifying the Metal Ions**:
- The options given are:
- Serum 2+ (which seems to be a typo and likely refers to some metal ion),
- Ni²⁺ (Nickel),
- Cu²⁺ (Copper),
- Mn²⁺ (Manganese).

3. **Reactions of DMG**:
- DMG forms a characteristic rosy red precipitate when it reacts with nickel ions in solution. This is a well-known qualitative test for nickel.

4. **Analyzing Each Option**:
- **Serum 2+**: Not a standard notation for any known metal ion.
- **Ni²⁺**: Known to form a rosy red precipitate with DMG.
- **Cu²⁺**: Forms a different color precipitate (usually a light pink or beige) with DMG.
- **Mn²⁺**: Does not form a precipitate with DMG.

5. **Conclusion**:
- Based on the above analysis, the correct answer is **Ni²⁺**, as it is the only ion that forms a rosy red crystalline precipitate with DMG.

### Final Answer:
DMG gives a rosy red crystalline precipitate with **Ni²⁺**.

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