`NiCl_(2)+2dmg overset(NH_(4)OH)toNi(dmg)_(2)darr`

Options

A. For precipitate formation formation reaction
B. For precipitate dissolution reaction
C. For precipitate exchange reaction
D. For no reaction

Answer

To solve the given question regarding the reaction of Nickel(II) chloride with dimethylglyoxime (DMG) in the presence of ammonium hydroxide, we will analyze the reaction step by step.

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactants in the reaction are Nickel(II) chloride (NiCl₂) and dimethylglyoxime (DMG). The presence of ammonium hydroxide (NH₄OH) indicates that it may be used to create a suitable environment for the reaction.

**Hint**: Look for the chemical formulas and identify the compounds involved.

2. **Understand the Reaction**:
The reaction can be summarized as:
\[ \text{NiCl}_2 + 2 \text{DMG} \overset{\text{NH}_4\text{OH}}{\rightarrow} \text{Ni(DMG)}_2 \]
Here, Nickel(II) chloride reacts with two moles of DMG to form a complex, Nickel dimethylglyoxime (Ni(DMG)₂).

**Hint**: Recognize that DMG acts as a ligand that coordinates with Nickel to form a complex.

3. **Formation of Precipitate**:
The product, Ni(DMG)₂, is a complex that precipitates out of the solution, which is indicated by the downward arrow (↓) in the reaction. This means that a solid is formed from the reactants.

**Hint**: A downward arrow in a chemical equation indicates the formation of a precipitate.

4. **Classify the Reaction Type**:
Since a precipitate is formed from the reactants, this reaction can be classified as a precipitate formation reaction. There were no precipitates present in the reactants, but one was formed in the products.

**Hint**: Consider the definitions of different types of reactions to classify correctly.

5. **Choose the Correct Option**:
Based on the analysis, the correct classification of the reaction is a precipitate formation reaction. Therefore, the answer is option A.

**Hint**: Review the definitions of the other options to confirm that they do not apply to this reaction.

### Final Answer:
The correct option for the reaction is **A: Precipitate formation reaction**.