Final answer:
There are four structural isomers for C4H8O ethers with no sp² hybridised atoms, which are 1-methoxypropane, 2-methoxypropane, 1-ethoxypropane, and 2-ethoxypropane.
Step-by-step explanation:
The student has asked how many structural isomers exist for C₄H₈O which are ethers with no sp² hybridised atoms. To answer this, we should consider only ethers which are molecules that have an oxygen atom connected to two alkyl or aryl groups with no double bonds (because there are no sp² hybridised carbons). We can either have a methoxy propane group, or a ethoxyethane group based on how the oxygen is connected to the carbons.
Considering different possibilities leads us to the following structures:
- 1-methoxypropane (normal propyl ether)
- 2-methoxypropane (isopropyl ether)
- 1-ethoxypropane
- 2-ethoxypropane
These are the four possible structural isomers for C₄H₈O ethers with all carbons in sp³ hybridisation. Thus, the answer to the student's question is b. 4.