QCM : Understanding Isomerism in Chemistry — 10 questions

Explication

Enantiomers are molecules that are non-superimposable mirror images of each other and exhibit optical activity by rotating plane-polarized light in opposite directions. Diastereomers are stereoisomers that are not mirror images, isomers are compounds with the same molecular formula but different structures, and meso compounds are achiral molecules with internal symmetry. Therefore, 'enantiomers' is the correct term for optical isomers that are mirror images.

Explication

The primary cause of geometric isomerism is restricted rotation around a double bond or within cyclic structures, preventing free interchange of groups and creating different spatial arrangements such as cis- and trans- isomers.

Explication

Coordination compounds are primarily known for their role in facilitating electron transfer and catalysis in chemical and biological systems, due to their ability to bind and activate various molecules, making them essential in processes like enzymatic reactions and industrial catalysis.

Explication

The concept of chirality in coordination complexes was first established and recognized in scientific literature in the 1920s, when the study of stereochemistry in inorganic chemistry began to develop, marking the early recognition of chiral coordination compounds.

Explication

Cis-trans isomerism is a type of geometric isomerism in coordination compounds where the spatial arrangement of similar ligands differs, with cis-isomers having similar ligands on the same side and trans-isomers having them on opposite sides. This affects the physical properties of the compounds.

Explication

William Miller is credited with developing the first polarimeter, the instrument used to measure optical activity. Louis Pasteur contributed to the understanding of chirality and optical activity but did not develop the measurement instrument. Michael Faraday and Alexander Bain are associated with other scientific achievements unrelated to optical activity measurement.

Explication

Bidentate ligands are capable of forming two bonds with the central metal atom, creating chelate rings. This multidentate bonding results in a more stable complex due to the chelate effect, which makes them preferred for applications requiring maximum stability.

Explication

Cis- and trans- isomers are distinguished by the relative positions of similar groups: in cis-isomers, these groups are on the same side, while in trans-isomers, they are on opposite sides. This difference affects their physical properties, such as boiling point and solubility, which is a key feature in their identification.

Explication

Optical isomers are non-superimposable mirror images due to chirality, known as enantiomers, and they exhibit optical activity. Geometric isomers differ in the spatial arrangement of groups around a bond or a ring, such as cis- and trans- isomers, but are not mirror images. Therefore, the primary difference is that optical isomers are mirror images, whereas geometric isomers are distinguished by the position of groups relative to each other.

Explication

Optical isomers are naturally occurring in biological molecules such as amino acids and sugars, where their optical activity plays a crucial role in biological functions and pharmaceutical applications.