Page 47 - Practical-workbook-organic-3 isa

❖ Complete the following statements:

1. Rank the following molecules in the order of the one with most de-shielded proton(s)

to the one with least de-shielded proton(s) (CH3, CH2, CH4, CH)

………>………>………>………

2. Higher electronegativity of the atom that the proton is attached to, the proton
is…………..shielded; the proton has a………….chemical shift.

3. If a proton is more shielded, then it has …………..chemical shift.

❖ Arrange in a decreasing order the values of the chemical shift (ppm) of

the proton attached to *C.

3
1 2

………….>……….>………….

1
❖ Assign the H NMR spectra (say which signal belongs to which atom) of these compounds
and explain the multiplicity of the signals:

No. Structure NMR spectra Assignment

H 0.97 (3H, t, J = 7

Hz), 1.42 (2H, sextet, J =
1. 7 Hz), 2.00 (2H, quintet,
J = 7 Hz), 4.40 (2H, t, J =

7 Hz).

H 1.00 (3H, t, J = 7 Hz),

1.75 (2H, sextet, J = 7
2.
Hz), 2.91 (2H, t, J = 7

Hz), 7.4–7.9 (5H, m).

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