What is the expected multiplicity of the signal of the circled hydrogen atoms in a 1H NMR spectrum?

Question

BlackTom AI · Accepted Answer

Begin by identifying how the multiplicity in 1H NMR arises: a proton’s signal is split by neighboring nonequivalent protons, and the splitting follows the n+1 rule, where n is the number of neighboring hydrogens.

Option a: doublet. This would occur if the circled hydrogen were coupled to exactly one neighboring hydrogen. If there were two or more neighbors, the splitting would be more complex than a simple doublet, so thisSingle-neighbor scenario is likely incorrect here.

Option b: singlet. A singlet means there are no neighboring hydrogens that can couple with the circled proton, or all couplings cancel out. If the circled hydrogen is adjacent to any hydrogen-bearing carbon, some coupling would typically appear, making a singlet unlikely unless the neighboring substituents decouple or are magnetically equivalent with no coupling, which is unusual in a standard hydrocarbon context.

Option c: triplet. According to the n+1 rule, if the circled hydrogen has two neighboring hydrogens on an adjacent carbon (i.e., it is split by two equivalent protons), the signal will appear as a triplet (3 lines). This is a common pattern for a CH group flanked by two equivalent H on the next carbon, or a CH2 group adjacent to a CH2 or CH3 where the coupling to those two equivalent protons produces three peaks.

Option d: quartet. A quartet would arise if the circled proton were coupled to three neighboring hydrogens. If there were three equivalent protons attached to the neighboring carbon, the splitting would yield four lines. This would require the circled hydrogen to be near a CH3 group as the coupling partner, which is not implied by the circled position alone.

Thus, the most consistent explanation—given the circled hydrogen’s coupling to two equivalent neighboring hydrogens—is that the signal should be a triplet. The other options describe splittings that would require different neighboring proton counts or arrangements, which do not align with the typical two-neighbor scenario.

MUF0042 Chemistry Unit 2 - Semester 2, 2025 8.20 Quiz: NMR Spectroscopy

What is the expected multiplicity of the signal of the circled hydrogen atoms in a 1H NMR spectrum?

查看解析

登录即可查看完整答案

类似问题

Consider the following molecule. How many unique signals would be observed in the 1H NMR spectrum of this molecule?

The splitting pattern for a compound with molecular formula C3H5OCl gave a quartet and a triplet. Which is the most likely structure for this compound?

A compound has the molecular formula C5H10O and the 1H-NMR spectrum contains four peaks. The compound could be

A compound has the molecular formula C5H10O and the 1H-NMR spectrum contains four peaks. The compound could be

What is the expected multiplicity of the signal of the circled hydrogen atoms in a 1H NMR spectrum?

The 1H NMR of 2-bromomethylpropane will consist of

How many signals would you expect to see in the 1H NMR spectrum of CH3CH2CH3?

Q15 V3The high resolution 1H NMR spectrum of a molecule is shown below. The molecule is most likely to be

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单