Which compound gives effervescence with sodium metal but not with sodium bicarbonate?

Options

A. Ethanol
B. Ethanoic acid
C. Ethanal
D. Ester

Explanation

To determine which compound gives effervescence with sodium metal but not with sodium bicarbonate, we can follow these steps:

### Step 1: Understand the Reactions
- Sodium metal (Na) reacts with certain compounds to produce hydrogen gas (H₂), which leads to effervescence.
- Sodium bicarbonate (NaHCO₃) reacts with acidic compounds to produce carbon dioxide gas (CO₂), which also leads to effervescence.

### Step 2: Identify the Compound
- We need a compound that reacts with sodium metal to produce hydrogen gas but does not react with sodium bicarbonate to produce carbon dioxide gas.
- Alcohols are known to react with sodium metal to release hydrogen gas but do not react with sodium bicarbonate.

### Step 3: Consider Alcohols
- Among the alcohols, ethanol (C₂H₅OH) is a common example.
- When ethanol reacts with sodium metal, the reaction is as follows:
\[ \text{C}_2\text{H}_5\text{OH} + \text{Na} \rightarrow \text{C}_2\text{H}_5\text{ONa} + \text{H}_2 \uparrow \]
This reaction produces sodium ethoxide and hydrogen gas, causing effervescence.

### Step 4: Check Reaction with Sodium Bicarbonate
- Ethanol does not react with sodium bicarbonate:
\[ \text{C}_2\text{H}_5\text{OH} + \text{NaHCO}_3 \rightarrow \text{No reaction} \]
Therefore, there is no effervescence when ethanol is mixed with sodium bicarbonate.

### Conclusion
- The compound that gives effervescence with sodium metal but not with sodium bicarbonate is **ethanol (C₂H₅OH)**.

### Final Answer
**Ethanol (C₂H₅OH)**

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