Among the following which metal cation gives red precipitate with dimethyl glyoxime:

Options

A. `Li^(+)`
B. `Ni^(+2)`
C. `Mg^(+2)`
D. `Pb^(+2)`

Answer

To solve the question, we need to identify which metal cation among the given options produces a red precipitate when reacted with dimethylglyoxime (DMG). The options provided are:

1. Lithium ion (Li⁺)
2. Nickel ion (Ni²⁺)
3. Magnesium ion (Mg²⁺)
4. Lead ion (Pb²⁺)

**Step 1: Understanding the Reaction with Dimethylglyoxime (DMG)**
- Dimethylglyoxime is a reagent commonly used to detect the presence of nickel ions in a solution. When nickel (Ni²⁺) reacts with dimethylglyoxime, it forms a complex that precipitates out of solution.

**Step 2: Identifying the Precipitate**
- The complex formed between nickel ions and dimethylglyoxime is known to be cherry red in color. This characteristic color is a key indicator of the presence of nickel ions.

**Step 3: Analyzing Other Options**
- Lithium (Li⁺), magnesium (Mg²⁺), and lead (Pb²⁺) do not form a similar red precipitate with dimethylglyoxime. Therefore, they can be ruled out as options.

**Step 4: Conclusion**
- Since nickel (Ni²⁺) is the only metal cation that gives a red precipitate with dimethylglyoxime, the correct answer is:

**Answer: Nickel ion (Ni²⁺)**

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