Question

Please complete the table given the following IR spectrum! Thank you!

3324.10cm-1.86.06%T 1% 2956.20cm-1, 76.48% ! 2859.20cm-1, 74.06%T 2928.22cm-1, 64.55%T 65- 64- 4000 3500 3000 2500 2000 cm-1

Answer 1

The attached IR spectra has only few signals. But these are most characteristic signals. So now we will discuss about these signals and write the details in the given table.

IR spectral details:

• At 3324 cm-1 there is a very broad signal which is more prominent and characteristic stretching signal of O-H bond vibration frequencies. Therefore, there must be a hydroxyl (-OH alcohol) group in the compound
• There -OH group does not belongs to any acid but it belongs to an alcohol compound.
• One more important signal which present around 2928 cm-1 region. This signal is corresponding to the C-H stretch of sp3 hybridized carbon. So, there is a -CH2- or -CH3 groups present in the compound along with hydroxyl group.
• There is one more signal at 2859 cm-1 which is corresponding to the C-H sp2 stretch. So, we may have doubly bonded carbon here.

So, if we observe, overall, the compound is a alcohol. The filled table with all given IR details given below:

pure ester peak cm-1 pure ester peak % T Specific bond vibration functional group 3324 O-H stretch -OH 2928 C-H sp3 stretch -CH3 2859 C-H sp2 stretch =CH-