Which gas is formed on heating sodium propanoate with lime?

Options

A. Methane
B. Ethane
C. Propane
D. Butane

Answer

To determine which gas is formed when sodium propanoate is heated with lime, we can follow these steps:

### Step 1: Identify the Reactants
The reactants in this reaction are sodium propanoate (CH3CH2COONa) and lime (which is primarily calcium oxide, CaO).

**Hint:** Look for the chemical formula of sodium propanoate and understand what lime is composed of.

### Step 2: Understand the Reaction Type
The reaction that occurs when sodium propanoate is heated with lime is known as a decarboxylation reaction. In this type of reaction, a carboxyl group (-COOH) is removed from the compound, releasing carbon dioxide (CO2) and forming an alkane.

**Hint:** Recall the definition of decarboxylation and what happens to the carboxyl group.

### Step 3: Write the Reaction
The decarboxylation of sodium propanoate can be represented as follows:
\[ \text{CH}_3\text{CH}_2\text{COONa} + \text{CaO} \rightarrow \text{C}_2\text{H}_6 + \text{Na}_2\text{CO}_3 \]

In this reaction, sodium propanoate reacts with lime (CaO) to produce ethane (C2H6) and sodium carbonate (Na2CO3).

**Hint:** Make sure to balance the chemical equation and identify the products formed.

### Step 4: Identify the Gas Produced
From the reaction, we can see that the gas produced is ethane (C2H6).

**Hint:** Check the products of the reaction and identify which one is a gas at room temperature.

### Final Answer
The gas formed on heating sodium propanoate with lime is **ethane (C2H6)**.