Isomers are defined as the compounds which have same formula but different in arrangement.
So, Isomers have the same number of atoms in each element.
According to the given examples, CH₃CH₂OH has the chemical formula as C₂H₆O while CH₃CHO has C₂H₅O. So, the number of atoms in each element is different for the given examples. Hence, CH₃CH₂OH and CH₃CHO are not isomers of each other.
