Which of the following strict procedural transformations performed on a standard 2D Fischer projecti — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

A $180^\circ$ in-plane rotation safely swaps horizontal and vertical axes symmetrically, preserving configuration. An even number of interchanges (like 2 swaps) mathematically preserves configuration (one swap inverts, a second reverts). Holding one group fixed and rotating the other three is topologically equivalent to a 3D rotation, preserving the configuration. A $90^\circ$ rotation violently inverts the stereochemistry (R becomes S).