Which of the following is the correct order of priorities in the R,S system?
A) aldehyde carboxyl ketone primary alcohol
B) carboxyl ketone aldehyde primary alcohol
C) primary alcohol aldehyde ketone carboxyl
D) primary alcohol ketone carboxyl aldehyde

Question

Which of the following is the correct order of priorities in the R,S system?
A) aldehyde > carboxyl > ketone > primary alcohol
B) carboxyl > ketone > aldehyde > primary alcohol
C) primary alcohol > aldehyde > ketone > carboxyl
D) primary alcohol > ketone > carboxyl > aldehyde

Quizplus · Accepted Answer

In the R,S system of nomenclature, priorities are assigned based on atomic number; the higher the atomic number, the higher the priority. Functional groups with more bonds to oxygen (or other heteroatoms) typically have higher priority. The carboxyl group, having two oxygen atoms, is given the highest priority, followed by the ketone and aldehyde (which are prioritized by the additional carbon in the ketone), and finally the primary alcohol.

Which of the Following Is the Correct Order of Priorities