Which of the following is not isomeric with diethyl ether?
Ketone cannot be an isomer of ether. No matter how you arrange diethyl ether, you cannot get a ketone compound.
First one is simple right? Just remove one carbon on one side and add to the other side.
C2H5−O−C2H5→C3H7−O−CH3
It can also become an alcohol. We need to add one hydrogen to the oxygen and shift it to the end.
C2H5−O−C2H5→CH3−CH2−CH2−CH2−OH
For the third one, follow a similar procedure as above. Just use a 3 carbon chain.