Question

Is cis, trans isomerism possible in alkanes?

Short answer

Explain your answer. Answer: No, cis, trans isomerism is not possible in alkanes. This is because alkanes only have single covalent bonds (sigma bonds) between carbon atoms and no cyclic structures, allowing free rotation of atoms or groups around these bonds. As a result, there are no different spatial arrangements of atoms or groups in alkanes to exhibit cis, trans isomerism.

Step-by-step solution

Understanding the structure and bonding of alkanes

Alkanes are hydrocarbons consisting of carbon and hydrogen atoms only. They have a general molecular formula of CnH2n+2, where n is the number of carbon atoms. Alkanes contain only single covalent bonds between carbon atoms, known as sigma (σ) bonds. These sigma bonds do not restrict the rotation of atoms or groups of atoms around the bond.

Considering the cis, trans isomerism in alkanes

Cis, trans isomerism is a type of stereoisomerism that occurs due to the restricted rotation around particular types of bonds, leading to different spatial arrangements of atoms or groups. The restricted rotation is usually observed in carbon-carbon double bonds (C=C) and in cyclic compounds where atoms or groups always stay on either side of a ring.

Comparing the bonding in alkanes with the requirement for cis, trans isomerism

Since alkanes do not have carbon-carbon double bonds or any cyclic structures, there is no possibility of restricted rotation around any of the sigma bonds in alkanes. Hence, atoms or groups in alkanes are free to rotate around single covalent bonds, which prevents any possibility of cis, trans isomerism in alkanes.

Conclusion

Cis, trans isomerism is not possible in alkanes. It is because alkanes only have single covalent bonds (sigma bonds) between carbon atoms and no cyclic structures, allowing free rotation of atoms or groups around these bonds. As a result, there are no different spatial arrangements of atoms or groups in alkanes to exhibit cis, trans isomerism.