Identify the dehydration product or products of a) ethanol, b) button-2-ol

Dehydration is a process in which an alcohol loses a molecule of water and leaves behind an alkene. The OH group is removed along with an H from any adjacent carbon atom. To work out the answer, firstly draw the structure of the alcohol in the question, and then work out the product or products.

a) Ethanol's structure is CH₃CH₂OH. There is only one adjacent carbon atom, and therefore only one possible product: H₂C=CH₂, also known as ethene. The full reaction is: CH₃CH₂OH ---> H₂C=CH₂ + H₂O

b) Butan-2-ol's structure is CH₃CH(OH)CH₂CH₃. There are two carbons adjacent to the C(OH) group, so there are two possible products: H₂C=CHCH₂CH₃ and CH₃CH=CHCH₃. Both have the same molecular formulae (C₄H₈), but they are not the same molecule; therefore they are structural isomers.