Among the options provided, the condensed structural formula that represents an unsaturated compound is CH3CH=CHCH3 (option A).
To understand why, we need to distinguish between saturated and unsaturated compounds:
- Saturated compounds
- Unsaturated compounds
have only single bonds between carbon atoms. This means they are ‘saturated’ with hydrogen atoms, and each carbon is bonded to as many hydrogen atoms as possible. Examples include CH3CH2CH3 (option B), CH3CH3 (option C), and CH4 (option D).
contain at least one double bond (or triple bond) between carbon atoms. This means they have fewer hydrogen atoms than saturated compounds. For instance, CH3CH=CHCH3 has a double bond between two carbon atoms, making it an unsaturated compound.
Thus, when comparing the options:
- A) CH3CH=CHCH3 – This has a double bond, indicating it is unsaturated.
- B) CH3CH2CH3 – This is a saturated compound with no double or triple bonds.
- C) CH3CH3 – This is also saturated with only single bonds.
- D) CH4 – A saturated compound, as it has no multiple bonds.
In conclusion, option A is the correct choice as it represents an unsaturated compound due to the presence of a double bond.