X is heated with soda lime and gives ethane, X is

Options

A. ethanoic acid
B. methanoic acid
C. propanoic acid
D. None of these

Explanation

To solve the question "X is heated with soda lime and gives ethane, X is," we need to identify the compound X that, when heated with soda lime, produces ethane. Let's break down the solution step by step.

### Step 1: Understanding Soda Lime
Soda lime is a mixture of sodium hydroxide (NaOH) and calcium oxide (CaO). It is commonly used in decarboxylation reactions, where a carboxylic acid loses a carbon dioxide molecule (CO₂) to form an alkane.

### Step 2: Analyzing the Options
We need to analyze the given options to determine which carboxylic acid, when subjected to decarboxylation with soda lime, produces ethane (C₂H₆).

1. **Option 1: Ethanoic Acid (Acetic Acid)**
- Structure: CH₃COOH
- Upon heating with soda lime, it would undergo decarboxylation to produce methane (CH₄) and CO₂, not ethane.
- **Conclusion**: This option is incorrect.

2. **Option 2: Methanoic Acid (Formic Acid)**
- Structure: HCOOH
- When heated with soda lime, it would produce carbon dioxide (CO₂) and hydrogen (H₂), not ethane.
- **Conclusion**: This option is incorrect.

3. **Option 3: Propionic Acid**
- Structure: CH₃CH₂COOH
- When heated with soda lime, it undergoes decarboxylation, losing CO₂ and forming ethane (C₂H₆).
- **Conclusion**: This option is correct.

4. **Option 4: Butanoic Acid**
- Structure: CH₃(CH₂)₂COOH
- When heated with soda lime, it would produce propane (C₃H₈) and CO₂, not ethane.
- **Conclusion**: This option is incorrect.

### Step 3: Final Answer
Based on the analysis, the compound X that, when heated with soda lime, gives ethane is **Propionic Acid (Option 3)**.