Whether the spectrum is consistent with the compound that contains C ≡ C or not should be explained and the absence of peak at 2300 − 2100 cm -1 should be explained. Concept introduction: IR spectroscopy is spectroscopic method to identify the structure of organic compounds. When IR is passed through the sample, different bonds vibrate at different frequencies of IR by absorbing IR light. In IR spectrum energy in terms of wavenumber( cm -1 ) is the horizontal axis and intensity is the vertical axis. As different molecules have different bonds of varying strength so they absorb IR light of different frequencies. This results in different absorption bands in the IR spectrum characteristic to that bond. IR region is divided into 3 regions, near, mid and far IR region. The mid-IR region extends from 4000 − 600 cm -1 and it is the most important region as approximately all organic compounds absorb in this region. The allowed vibrational energy levels for IR transition is as follows: E = h ν ο ( ν + 1 ) Where, E is IR energy absorbed by a molecule. h is Planck's constant. ν ο is zero point vibrational level. ν is vibrational level with integer value of 1,2,3,4.....

Question

The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A compound containing no nitrogen exhibits strong, broad absorption across the 2500-3300 cm-1 region, accompanied by 2200 (w) and 1715 (s) cm-1bands.Relative absorption intensity: (s)=strong, (m)=medium, (w)=weak. What functional class(es) does the compound belong to? List only classes for which evidence is given here. Attach no significance to evidence not cited explicitly.Do not over-interpret exact absorption band positions. None of your inferences should depend on small differences like 10 to 20 cm-1. The functional class(es) of this compound is(are)fill in the blank 1.(Enter letters from the table below, in any order, with no spaces or commas.) a. alkane (List only if no other functional class applies.) b. alkene h. amine c. terminal alkyne i. aldehyde or ketone d. internal alkyne j. carboxylic acid e. arene k. ester f. alcohol l. nitrile g. ether

Answer 1

Question

Chapter 21, Problem 3Q

Interpretation Introduction

Interpretation:

Whether the spectrum is consistent with the compound that contains C≡C or not should be explained and the absence of peak at 2300−2100 cm-1 should be explained.

Concept introduction:

IR spectroscopy is spectroscopic method to identify the structure of organic compounds. When IR is passed through the sample, different bonds vibrate at different frequencies of IR by absorbing IR light. In IR spectrum energy in terms of wavenumber( cm-1 ) is the horizontal axis and intensity is the vertical axis.

As different molecules have different bonds of varying strength so they absorb IR light of different frequencies. This results in different absorption bands in the IR spectrum characteristic to that bond.

IR region is divided into 3 regions, near, mid and far IR region. The mid-IR region extends from 4000−600 cm-1 and it is the most important region as approximately all organic compounds absorb in this region.

The allowed vibrational energy levels for IR transition is as follows:

E=hνο(ν+1)

Where,

E is IR energy absorbed by a molecule.

h is Planck's constant.

νο is zero point vibrational level.

ν is vibrational level with integer value of 1,2,3,4.....

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