Question

Grignard reagent RMgBr (P) reacts with water and forms a gas (Q). One gram of Q occupies 1.4 dm$^3$ at STP. (P) on reaction with dry ice in dry ether followed by H$_3$O$^+$ forms compound (Z). 0.1 mole of (Z) will weigh _________ g (Nearest integer).

Hint:

Grignard reagents with CO$_2$ always form carboxylic acids.

Answer 1

Correct Answer: 6

Step 1: Identifying gas Q.
At STP, 22.4 L = 1 mol
\[ \text{Molar mass of Q} = \frac{22.4}{1.4} = 16 \Rightarrow \text{CH}_4 \]
Step 2: Identifying R.
Gas formed is methane $\Rightarrow R = \text{CH}_3$.
Step 3: Product Z.
Reaction with CO$_2$ gives CH$_3$COOH.
Molar mass of CH$_3$COOH = 60 g mol$^{-1}$.
Step 4: Mass of 0.1 mole.
\[ 0.1 \times 60 = 6 \text{ g} \]