How many unique 1h nmr signals exist in the spectrum of the following compound?

Question

Question:

How many unique 1h nmr signals exist in the spectrum of the following compound?

Answer & Explanation:

13C and 1H- NMR Note:13 and 1 are superset.
The number of peaks in 1H NMR indicates the number of chemically different hydrogen atoms respectively in a molecule. The number of peaks in 13C NMR indicates the number of chemically different carbon atoms in a molecule.

The given compound is shown below.

Given compound
The above molecule has three peaks in the 1H NMR and 13C NMR spectra. There exists a plane of symmetry in the molecule. The plane passes through the third carbon because of which the first and fifth carbon are same and second and fourth carbon are same.
The non-equivalent hydrogens are shown below.

Non-equivalent hydrogens
There are three types of hydrogens. First are the hydrogens of OH group. Second type is of the −CH2 group of second and fourth carbon and the third type is of the −CH2 group of third carbon. Therefore, three peaks are observed in the 1H NMR spectrum.
The non-equivalent carbons are shown below.

Non-equivalent carbons
There are three types of carbons. First are the carbons of COOH group. Second are the second and fourth carbon and third type is of the third carbon. Therefore, three peaks are observed in the 13C NMR spectrum.

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Sam Professor 2 years 1 Answer 749 views 0

Answer ( 1 )

  1. 13C and 1H- NMR Note:13 and 1 are superset.
    The number of peaks in 1H NMR indicates the number of chemically different hydrogen atoms respectively in a molecule. The number of peaks in 13C NMR indicates the number of chemically different carbon atoms in a molecule.
    Answer and Explanation:
    The given compound is shown below.

    Given compound
    The above molecule has three peaks in the 1H NMR and 13C NMR spectra. There exists a plane of symmetry in the molecule. The plane passes through the third carbon because of which the first and fifth carbon are same and second and fourth carbon are same.
    The non-equivalent hydrogens are shown below.

    Non-equivalent hydrogens
    There are three types of hydrogens. First are the hydrogens of OH group. Second type is of the −CH2 group of second and fourth carbon and the third type is of the −CH2 group of third carbon. Therefore, three peaks are observed in the 1H NMR spectrum.
    The non-equivalent carbons are shown below.

    Non-equivalent carbons
    There are three types of carbons. First are the carbons of COOH group. Second are the second and fourth carbon and third type is of the third carbon. Therefore, three peaks are observed in the 13C NMR spectrum.

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