Instructions: Refer to the structure of 3-methylbutan-2-one below to answer the following question(s). Refer to instructions. What is the splitting pattern for the hydrogens in 3-methylbutan-2-one labeled A, B, and C, respectively?
A) singlet, singlet, singlet
B) singlet, septet, quartet
C) singlet, septet, doublet
D) singlet, septet, doublet, doublet

Question

Instructions: Refer to the structure of 3-methylbutan-2-one below to answer the following question(s).  Refer to instructions. What is the splitting pattern for the hydrogens in 3-methylbutan-2-one labeled A, B, and C, respectively?
A) singlet, singlet, singlet 
B) singlet, septet, quartet 
C) singlet, septet, doublet 
D) singlet, septet, doublet, doublet

Quizplus · Accepted Answer

Hydrogen A is a singlet because it is not directly adjacent to any other hydrogen atoms. Hydrogen B is a part of a methylene group (-CH2-) that is adjacent to a methyl group (-CH3), so it will experience a septet splitting pattern due to the three equivalent hydrogens on the neighboring methyl group. Hydrogen C is also a part of a methylene group but is adjacent to a carbonyl group (-C=O), so it will experience a doublet splitting pattern due to the one proton on the carbonyl carbon. Therefore, the splitting pattern for the hydrogens in 3-methylbutan-2-one labeled A, B, and C, respectively is singlet, septet, doublet, and the best choice is C.

Instructions: Refer to the Structure of 3-Methylbutan-2-One Below to Answer