Question

Which of the following ethers is gaseous at room temperature ?

• A. 1 - Methoxypropane
• B. 1 - Ethoxypropane
• C. Methoxyethane
• D. Ethoxyethane

Hint:

Fewer carbon atoms means a smaller molecular mass and a lower boiling point. Pick the smallest ether.

Answer 1

The Correct Option is C

Step 1: Write the formulas:
(A) $\text{C}_4\text{H}_{10}\text{O}$ (methyl propyl ether).
(B) $\text{C}_5\text{H}_{12}\text{O}$.
(C) $\text{C}_3\text{H}_8\text{O}$ (methyl ethyl ether).
(D) $\text{C}_4\text{H}_{10}\text{O}$ (diethyl ether).

Step 2: Link size to state:
Ethers cannot form hydrogen bonds with each other, so the only attraction is weak van der Waals and dipole forces. These grow with molecular size.
The lightest, $\text{C}_3\text{H}_8\text{O}$, boils near 7 degrees C. The 4-carbon ethers boil around 35-39 degrees C and the 5-carbon ether near 64 degrees C.

Step 3: Decide:
At room temperature (about 25 degrees C), only methoxyethane is above its boiling point, so it is a gas.

Final Answer:
Methoxyethane is gaseous, option (C). \[ \boxed{\text{Methoxyethane (C)}} \]