Under the strict application of Cahn-Ingold-Prelog (CIP) sequence rules for determining R/S absolute — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

Priority is determined by the atomic number of the directly attached atom. In option C, Oxygen (8) > Nitrogen (7) > Carbon (6) > Hydrogen (1), which accurately reflects the correct descending CIP priority. In B, $-Ph$ has a Carbon attached to C,C,C, while $-CHO$ has a Carbon attached to O,O,H. $-CHO$ > $-Ph$, so B is incorrect.