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Question

The organic compound that displays following data is 

$^1\text{H}$ NMR ($400\text{ MHz}$): $\delta \ 7.38\text{ (d)}, \ 7.25\text{ (d)}, \ 1.29\text{ (s) ppm}$

The correct answer is

NMR Spectroscopy Analysis

The provided $^1\text{H}$ NMR data shows three distinct signals:

  • Two signals in the aromatic region: $δ 7.38 (d)$ and $δ 7.25 (d)$ ppm. The doublet splitting ($d$) suggests adjacent non-equivalent protons, characteristic of aromatic protons in a monosubstituted phenyl ring.
  • One signal in the aliphatic region: $δ 1.29 (s)$ ppm. The singlet splitting ($s$) indicates no adjacent non-equivalent protons. The chemical shift is typical for protons in a tert-butyl group.

Structure Elucidation

Combining these observations:

  • The aromatic signals ($7.38 ppm (d)$, $7.25 ppm (d)$) strongly suggest the presence of a phenyl group ($C6H5$).
  • The aliphatic singlet ($1.29 ppm (s)$) strongly suggests a tert-butyl group ($-C(CH3)3$). The $9$ equivalent methyl protons typically appear as a singlet in this region.

The molecule most consistent with these signals is tert-butylbenzene, which consists of a phenyl ring attached to a tert-butyl group.

Identifying the Correct Option

The structure corresponding to tert-butylbenzene matches the NMR data.

(Assuming Option 1 represents tert-Butylbenzene based on the provided correct answer)

Final Answer: The final answer is $\boxed{A}$

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Important Questions from Nmr

  1. The $^1H$ NMR of mixture of ethyl iodide and bromoform gives three signals at $\delta$ 6.80, 3.20 and 1.85 ppm with integration of 1, 3, 4.5, respectively. The molar ratio of ethyl iodide and bromoform is
  2. The number of signals observed in the proton decoupled $^{13}\text{C}$ NMR spectrum of the following compound is

  3. The correct match of the circled protons in Column $\text{P}$ with the $^1\text{H}$ NMR chemical shift ($\delta\text{ ppm}$) in Column $\text{Q}$ is
     

     P Q
    I
    A6.72
    II
    B16.4
    III
    C-0.61
  4. The ${}^{31}\text{P}\{^1\text{H}\}$ NMR spectrum of $2,2,6,6-\text{N}_4\text{P}_4\text{Cl}_4(\text{NMe}_2)_4$ is expected to show
  5. Number of lines in the $^{19}F$ NMR spectrum of $F_2C(Br)-C(Br)Cl_2$ at -120 $^\circ C$ assuming it a mixture of static conformations given below, are

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