How many isomers are there with the formula C3
H4
? Include both structural and geometric isomers. 5 2 3 6 4
The Correct Answer and Explanation is:
The molecular formula C3H4 represents a hydrocarbon with three carbon atoms and four hydrogen atoms. To find the number of isomers, we consider both structural and geometric isomers.
Step 1: Recognizing the Formula
The formula C3H4 suggests a degree of unsaturation, meaning there is at least one double bond or a ring structure. By calculating the degree of unsaturation:
- Each carbon-hydrogen bond contributes 1 to the hydrogen count, and each carbon-carbon bond contributes 2 electrons (making a total of 2 hydrogens). This means that with C3H4, the degree of unsaturation is 2, which implies the presence of either two double bonds, a triple bond, or a ring structure.
Step 2: Structural Isomers
1. Propene (C3H6)
- This is the simplest straight-chain alkene with one double bond.
2. Allene (C3H4)
- This compound features a unique structure where two carbon atoms are part of a straight chain with a double bond between them and another carbon double-bonded to the second carbon. The two carbon-carbon double bonds are orthogonal, creating an interesting geometry.
Thus, there are 2 possible structural isomers for C3H4.
Step 3: Geometric Isomers
Geometric isomerism occurs when different groups are attached to a rigid structure (like a double bond or ring). In the case of C3H4, geometric isomerism is not possible because there are no double bonds with distinct substituents, and the available compounds are linear or simple, not giving rise to cis-trans isomerism.
Conclusion
There are 2 structural isomers of C3H4. Therefore, the correct answer is 2. Geometric isomers are not applicable in this case.
