The gas evolved on heating `CH_(3)MgBr` in methanol is :

Options

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

Answer

To determine the gas evolved when heating CH₃MgBr (a Grignard reagent) in methanol, we can follow these steps:

### Step 1: Identify the Reactants
We have CH₃MgBr (methylmagnesium bromide) and methanol (CH₃OH) as our reactants.

**Hint:** Recognize that CH₃MgBr is a Grignard reagent, which is a type of organomagnesium compound.

### Step 2: Understand the Nature of Grignard Reagents
Grignard reagents are highly reactive and can react with compounds containing acidic hydrogen atoms. Methanol has an acidic hydrogen atom attached to the oxygen.

**Hint:** Recall that Grignard reagents react with acids to form hydrocarbons and magnesium salts.

### Step 3: Analyze the Reaction
When CH₃MgBr reacts with methanol, the methyl group (CH₃⁻) from the Grignard reagent will attack the hydrogen atom of the hydroxyl group (-OH) in methanol. This leads to the formation of methane (CH₄) gas and a magnesium alkoxide.

**Hint:** Consider the transfer of the methyl group to the acidic hydrogen in methanol.

### Step 4: Write the Reaction Equation
The reaction can be represented as follows:
\[ \text{CH}_3\text{MgBr} + \text{CH}_3\text{OH} \rightarrow \text{CH}_4 (g) + \text{CH}_3\text{O}^-\text{MgBr}^+ \]

**Hint:** Identify the products of the reaction, focusing on the gaseous product.

### Step 5: Identify the Gas Evolved
From the reaction, we see that methane (CH₄) is produced as a gas.

**Hint:** Remember that gases are often less dense than liquids and can be easily identified in a reaction setup.

### Conclusion
The gas evolved on heating CH₃MgBr in methanol is methane (CH₄).

**Final Answer:** Methane (CH₄)