Given the following molecule: ${\mathrm{CH}}_3-\mathrm{CHBrClF}$, select the correct $R$ or $S$ configuration for the stereocenter carbon atom (the carbon bonded to Br, Cl, F, and H).

• A. Neither $R$ nor $S$ (achiral)
• B. $R$ configuration
• C. $S$ configuration
• D.

Answer: (B)

Verified step by step guidance

1. Identify the stereocenter: The carbon atom bonded to Br, Cl, F, and H is the stereocenter because it has four different substituents.
2. Assign priorities to the substituents based on atomic number according to the Cahn-Ingold-Prelog (CIP) rules: The higher the atomic number, the higher the priority. So, assign priorities to Br, Cl, F, and H.
3. Orient the molecule so that the substituent with the lowest priority (usually hydrogen) is pointing away from you (into the plane).
4. Trace a path from the highest priority substituent (1) to the second (2), then to the third (3).
5. Determine the configuration: If the path traced is clockwise, the configuration is R; if counterclockwise, it is S.