Question

Which of the following will not show
splitting of PMR signals :
(A) n-butane
(B) Ethyl formate
(C) 1,2-dichloroethane
(D) Toluene​

Answer 1

Explanation:

Splitting. NMR provides information on how many hydrogen neighbors exist for a particular hydrogen or group of equivalent hydrogens. ... If there is one hydrogen on the adjacent atoms, the resonance will be split into two peaks of equal size, a doublet.

Answer 2

Among the following, the compound that will not show splitting of PMR signals is 1, 2-dichloroethane. Thus, the correct option is (C) 1, 2-dichloroethane.

Explanation:

• PMR spectroscopy is Proton Magnetic Resonance spectroscopy.
• The splitting of signals in PMR spectroscopy is caused by the adjacent or neighbouring protons that are in a different environment than the absorbing proton.
• In n-butane ($\[C{H_3}C{H_2}C{H_2}C{H_3}\]$), two different types of protons, i.e., protons in different environments are present. Therefore, it will show splitting.
• In ethyl formate ($\[C{H_3}C{H_2}OCHO\]$), two non-equivalent protons are present. Therefore, it will show the splitting of PMR signals.
• In 1, 2-dichloroethane ($\[ClC{H_2}C{H_2}Cl\]$), all protons are equivalent and are in the same environment. Therefore, no splitting of PMR signals occurs in this case.
• In toluene ($\[{C_6}{H_5}C{H_3}\]$), protons in different environments are present. Therefore, it will show splitting.
• Thus, no splitting of PMR signals is observed in 1, 2-dichloroethane.

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