SCH4UC Name ___________________________________ Date ___________________________

Spectroscopy Worksheet

1) Determine the index of hydrogen deficiency (IHD) for each of the following:

a) C4H8O2 b) C5H12N2 c) C6H6

2) Determine the IHD for C3H5N, and propose a possible structure for the molecule.

3) Which of the following compounds would produce the IR spectrum shown below. Explain your reasoning.

a) ethaneb) ethenec) ethanold) ethanoic acide) ethanalf) ethanamine

4) Predict the IR bands and the bonds responsible for them in the region above 1500 cm—1 for the following:

a) propane b) propan-2-ol c) propene d) propanoic acid

5) The following peaks occur in the mass spectra of compounds containing carbon, hydrogen, and oxygen only. Suggest possible identities for the fragments responsible.

a) 15 b) 28 c) 29 d) 31e) 43 f) 45 g) 59 h) 77

6) The NMR spectrum for an ester with molecular formula, C4H8O2 is shown below. Deduce the structure of the compound.

7) The NMR spectrum of each of the following contains a singlet. Suggest the chemical shift range for the singlet.

8) The NMR spectrum shown below is of an alcohol. Work out the structure of the alcohol and state the multiplicity of the peak at δ = 4.0 ppm.

9)

Answers:

1a) 1 b) 1 c) 4

2) 2 CH3CH2CN or CHCCH2NH2 (other answers are also possible)

3) ethanol

4) a) 2850-3090 (C—H) b) 2850-3090 (C—H); 3200-3600 (O—H)

c) 2850-3090 (C—H); 1620-1680 (C=C)

d) 2850-3090 (C—H); 2500-3000 (O—H in COOH); 1700-1750 (C=O); 1050-1410 (C—O)

5a) CH3+ b) CO+, C2H4

+ c) C2H5+, HCO+ d) OCH3

+, CH2OH+

e) C3H7+, C2H3O+ f) COOH+, C2H5O+ g) C3H7O+, CH2COOH+, HCOOCH2

+

h) C6H5+

6) ethyl ethanoate

7a) 1.0 – 6.0 b) 2.0 – 2.5 c) 3.7 – 4.8

8) multiplicity 7 propan-2-ol

9) pentan-3-one