Which of protons, 1 to 4, in the following molecule gives a triplet signal in a 1H NMR spectrum?

Question

BlackTom AI · Accepted Answer

The molecule shown has four labeled protons/sets: 1 is a terminal CH3 on the far left, 2 is a CH with a methyl substituent, 3 is a CH2 adjacent to the carbonyl, and 4 is a terminal CH3 on the right end.

Option a (1): The leftmost CH3 (proton set 1) is attached to a CH (carbon 2). This CH (2) has a single hydrogen, so the CH3-1 protons couple to that one neighboring proton, giving a doublet rather than a triplet. They do not see two equivalent neighbors to give a triplet, so this is not correct.

Option b (2): Proton set 2 is a CH with one hydrogen. Its splitting comes from neighboring protons on carbons adjacent to it. On one side there is CH3-1 (3 protons) and on the other side there is CH2-3 (which has its own protons). The resulting pattern would be more complex than a simple triplet, not a clean triplet, so this option is not correct.

Option c (3): Proton set 3 is the CH2 adjacent to the carbonyl and to CH3-4. The CH2-3 protons are coupled to the three protons of CH3-4, which would produce a quartet for CH2-3, not a triplet. Additionally, CH2-3 is not coupled to exactly two equivalent protons; it couples to three, giving a quartet, so this option is incorrect.

Option d (4): Proton set 4 is the terminal CH3 on the right, which is adjacent to CH2-3 (which has two hydrogens). The three protons on CH3-4 split by the two equivalent protons on CH2-3 produce a triplet. This is the classic ethenic/alkyl “CH3–CH2–” pattern where the methyl next to a methylene appears as a triplet. Therefore, proton set 4 yields a triplet.

In summary, only the protons labeled 4 experience coupling to two equivalent neighboring protons, giving a triplet in the 1H NMR spectrum, while the others do not provide a simple triplet due to different neighboring proton counts and coupling patterns.

Which of protons, 1 to 4, in the following molecule gives a triplet signal in a 1H NMR spectrum?

View Explanation

Log in for full answers

Similar Questions

In a consumer society, many adults channel creativity into buying things

Economic stress and unpredictable times have resulted in a booming industry for self-help products

People born without creativity never can develop it

A product has a selling price of $20, a contribution margin ratio of 40% and fixed cost of $120,000. To make a profit of $30,000. The number of units that must be sold is: Type the number without $ and a comma. Eg: 20000

Which of the following statement regarding cost is correct:

Under the assumptions used in cost-volume-profit analysis, as the activity increases:

The CVP and break-even analysis are supported by a range of important assumptions. Which of the following is not an assumption of the CVP:

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler