In order to get propane gas which of the following should be subjected to soda lime decarboxylation?

Options

A. Sodium formate
B. Mixture of sodium acetate and sodium ethanoate
C. Sodium butyrate
D. Sodium propionate

Explanation

To determine which compound should be subjected to soda lime decarboxylation to obtain propane gas, we need to follow these steps:

### Step 1: Understand Decarboxylation
Decarboxylation is a chemical reaction that removes a carboxyl group (-COOH) from a carboxylic acid or its salt, resulting in the formation of an alkane. The reaction typically requires a strong base, such as sodium hydroxide (NaOH), and a dehydrating agent like calcium oxide (CaO), collectively known as soda lime.

**Hint:** Remember that decarboxylation requires a carboxylic acid salt.

### Step 2: Identify the Structure of Propane
Propane is an alkane with the molecular formula C3H8. Its structure can be represented as CH3-CH2-CH3. To obtain propane through decarboxylation, we need a carboxylic acid salt that, when decarboxylated, will yield three carbon atoms in the final product.

**Hint:** Look for a carboxylic acid salt that has a total of three carbon atoms.

### Step 3: Determine the Appropriate Carboxylic Acid Salt
The carboxylic acid salt that can be decarboxylated to yield propane is sodium butyrate (sodium butanoate), which has the structure CH3-CH2-COO-Na. When sodium butyrate undergoes decarboxylation, it releases carbon dioxide (CO2) and forms propane (C3H8).

**Hint:** Sodium butyrate is derived from butanoic acid, which has four carbon atoms. Removing one carbon atom during decarboxylation will yield propane.

### Step 4: Write the Decarboxylation Reaction
The reaction can be represented as follows:
\[ \text{Sodium Butyrate (CH}_3\text{CH}_2\text{COO-Na)} + \text{Soda Lime (NaOH + CaO)} \xrightarrow{\text{heat}} \text{Propane (C}_3\text{H}_8) + \text{Sodium Carbonate (Na}_2\text{CO}_3) \]

**Hint:** Ensure to balance the reaction and identify the products formed.

### Conclusion
The correct answer to the question is that sodium butyrate should be subjected to soda lime decarboxylation to obtain propane gas.

**Final Answer:** Sodium butyrate (option 3) is the correct choice.