During the qualitative analysis of salt with cation `y^(2+)` , addition of a reagent (X) to alkaline solution of the salt gives a bright red precipitate. The reagent (X) and the cation `(y^(2+))` present Question: respectively are:

Options

A. Dimethylglyoxime and `Ni^(2+)`
B. Dimethylglyoxime and `Co^(2+)`
C. Nessler's reagent and `Hg^(2+)`
D. Nessler's reagent and `Ni^(2+)`

Answer

To solve the question, we need to identify the cation \( y^{2+} \) and the reagent \( X \) that produces a bright red precipitate when added to an alkaline solution of the salt.

### Step-by-Step Solution:

1. **Understanding the Cation**: We know that the cation \( y^{2+} \) is a divalent cation. We need to consider common divalent cations that can form colored complexes.

2. **Identifying the Reagent**: The reagent \( X \) must be able to react with the cation \( y^{2+} \) in an alkaline medium to produce a bright red precipitate.

3. **Common Reagents and Their Reactions**:
- Nickel (Ni) ions can form a complex with Dimethylglyoxime (DMG) in alkaline conditions, resulting in a bright red precipitate of nickel dimethylglyoxime complex.
- Other cations like cobalt (Co) and copper (Cu) do not produce a bright red precipitate with DMG.

4. **Conclusion**: Based on the known reactions, the cation \( y^{2+} \) is likely Nickel \( (Ni^{2+}) \) and the reagent \( X \) is Dimethylglyoxime (DMG). When nickel ions react with DMG in an alkaline solution, they form a bright red precipitate.

### Final Answer:
- Cation \( y^{2+} \): Nickel \( (Ni^{2+}) \)
- Reagent \( X \): Dimethylglyoxime (DMG)