Which of the following statement is incorrect ?

Options

A. Almunium reacts with excess NaOH to give `Al(OH)_(3)`
B. `NaHCO_(3)` on heating gives `Na_(2)CO_(3)`
C. Pure sodium metal dissolves in liquid ammonia to give blue solution
D. NaOH reacts with glass to give sodium silicate

Answer

To determine which of the given statements is incorrect, we will analyze each option step by step.

### Step 1: Analyze Option 1
**Statement:** Aluminum reacts with excess NaOH to give Al(OH)₃.

**Analysis:**
- When aluminum reacts with excess sodium hydroxide (NaOH) in the presence of water, it forms sodium aluminate (NaAl(OH)₄) and hydrogen gas (H₂), not Al(OH)₃.
- The reaction can be represented as:
\[ 2 \text{Al} + 2 \text{NaOH} + 6 \text{H}_2\text{O} \rightarrow 2 \text{NaAl(OH)}_4 + 3 \text{H}_2 \]
- Therefore, this statement is incorrect.

### Step 2: Analyze Option 2
**Statement:** Na₂SO₃ on heating gives Na₂CO₃.

**Analysis:**
- Sodium sulfite (Na₂SO₃) does decompose upon heating to form sodium carbonate (Na₂CO₃) and sulfur dioxide (SO₂).
- The reaction can be represented as:
\[ \text{Na}_2\text{SO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{SO}_2 \]
- Thus, this statement is correct.

### Step 3: Analyze Option 3
**Statement:** Pure sodium metal dissolved in liquid ammonia gives a blue solution.

**Analysis:**
- When sodium metal is dissolved in liquid ammonia, it forms ammoniated electrons, which are responsible for the characteristic blue color of the solution.
- This process can be represented as:
\[ \text{Na} + \text{NH}_3 \rightarrow \text{Na}^+ + e^- \text{(ammoniated)} \]
- Therefore, this statement is correct.

### Step 4: Analyze Option 4
**Statement:** NaOH reacts with glass to give sodium silicate.

**Analysis:**
- Sodium hydroxide (NaOH) does react with silica (SiO₂) in glass to form sodium silicate (Na₂SiO₃).
- The reaction can be represented as:
\[ \text{NaOH} + \text{SiO}_2 \rightarrow \text{Na}_2\text{SiO}_3 + \text{H}_2\text{O} \]
- Thus, this statement is correct.

### Conclusion
After analyzing all the options, we find that:
- **Option 1 is incorrect** because aluminum does not react with excess NaOH to give Al(OH)₃.

### Final Answer
The incorrect statement is **Option 1**: Aluminum reacts with excess NaOH to give Al(OH)₃.

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