Question

$$C_2{H}_{6}O$$ is the molecular formula for two compounds A and B. They have a different structural formula.
A. What is this phenomenon known as?
B. Give the structural formula of A and B.
C. Write down their common and IUPAC names.
D. Mention the functional groups of A and B.

Answer 1

Hint: Sometimes there is more than one way to connect a given group of atoms into a molecular structure. They have the same formula but different structures which gives them their unique properties.

Complete step by step solution:

A. This is called isomerism. Isomers are the molecules which have the same molecular formula, but have a different arrangement of the atoms. They have the same empirical formula but they do not necessarily share similar physical and chemical properties.

B. The structural formula of A ($$C{H}_{3}C{H}_{2}OH$$) is

 The structural formula of B ($$C{H}_{3}OC{H}_3$$) is

C. Common name: Ethyl alcohol
    IUPAC name: Ethanol
   Common name: Dimethyl ether
    IUPAC name: Methoxymethane

D. The functional group of A is alcohol.
    The functional group of B is ether.

Additional Information:
At room temperature, dimethyl ether is a gas whereas ethanol is a liquid.
The dominant intermolecular attraction between ethanol molecules is hydrogen bonding whereas in dimethyl ether the major intermolecular attraction involves regular dipole moments.
Dimethyl ether has a melting point of -138°C and boiling -25°C while ethanol has a melting point of -117°C and boiling 78°C.

Note: These two compounds are functional isomers. There are even more types of isomers, mainly classified as chain isomers, position isomers, and functional group isomers.