`Zn(OH)_(2)darr+2NaOH to Na_(2) ZnO_(2)+2H_(2)O`

Options

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

Answer

To determine the type of reaction represented by the equation:

\[ \text{Zn(OH)}_2 + 2 \text{NaOH} \rightarrow \text{Na}_2\text{ZnO}_2 + 2 \text{H}_2\text{O} \]

we can follow these steps:

### Step 1: Identify the Reactants and Products
- The reactants are zinc hydroxide \((\text{Zn(OH)}_2)\) and sodium hydroxide \((\text{NaOH})\).
- The products are sodium zincate \((\text{Na}_2\text{ZnO}_2)\) and water \((\text{H}_2\text{O})\).

**Hint:** Look at the chemical formulas to identify what substances are involved in the reaction.

### Step 2: Analyze the State of Reactants
- Zinc hydroxide \((\text{Zn(OH)}_2)\) is indicated as a precipitate (solid) in the reaction.
- Sodium hydroxide \((\text{NaOH})\) is typically soluble in water.

**Hint:** Check if any of the reactants are solids, liquids, or gases to determine their state.

### Step 3: Analyze the State of Products
- Sodium zincate \((\text{Na}_2\text{ZnO}_2)\) and water \((\text{H}_2\text{O})\) are both soluble in water and do not form a precipitate.

**Hint:** Determine if the products are soluble or if they form a solid.

### Step 4: Determine the Type of Reaction
- Since the reaction starts with a precipitate \((\text{Zn(OH)}_2)\) and ends with soluble products \((\text{Na}_2\text{ZnO}_2\) and \(\text{H}_2\text{O})\), this indicates that the precipitate is dissolving into the solution.

**Hint:** Consider the changes in the state of matter from reactants to products to classify the reaction.

### Conclusion
Based on the analysis, this reaction is classified as a **precipitate dissolution reaction** because a solid precipitate is dissolving to form soluble products.

### Final Answer
The type of reaction is: **Precipitate Dissolution Reaction**.

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