JEE Main 2025 · 7 April · morning · Single correct · +4 / −1
Given below are two statements :
Statement I : Dimethyl ether is completely soluble in water. However, diethyl ether is soluble in water to a very small extent.
Statement II : Sodium metal can be used to dry diethyl ether and not ethyl alcohol.
In the light of given statements. choose the correct answer from the options given below
- (a) Statement I is false but Statement II are true
- (b) Statement I is true but Statement II is false
- (c) Both Statement I and Statement II are true
- (d) Both Statement I and Statement II are False
Answer and solution
Answer (c) Both Statement I and Statement II are true
Solution
Chemistry ma’am · 4 steps
Check two things: who can hydrogen bond with water, and who has an O–H for sodium to attack.
- Solubility of ethers. The ether oxygen has lone pairs, so it can accept a hydrogen bond from water. In dimethyl ether the two small methyl groups barely get in the way, so it mixes with water completely.
- Bigger alkyl groups. In diethyl ether the larger ethyl groups make most of the molecule hydrophobic. Only a small amount dissolves, about 7 g per 100 g of water. So Statement I is true.
- Drying with sodium. Ethers have no O–H bond, so sodium does not react with diethyl ether. It only reacts with any traces of water, which dries the ether. Ethanol has an O–H bond, so sodium attacks the alcohol itself: 2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂. So Statement II is true.
- So. Both statements are true, which is option (c).
The idea to keep. Ethers can only accept hydrogen bonds, so small ethers dissolve well and bigger ones barely do. With no acidic O–H, ethers survive sodium, while alcohols react with it.
Answer from the NTA final answer key. Solution by PrepWiser.