Question

1) The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A hydrocarbon exhibits no bands above 3000 but gives weak absorption at 2200 cm^-1.
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).(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 2) The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A compound containing C, H, and O exhibits strong, broad absorption band at 3430 cm-1, a sharp band at 3300, and a band at 2200 cm-1 (m). 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).(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 3) The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A C6 hydrocarbon exhibits bands between 3000-3100 (w), 2850-2960 (m), and at 1650 cm-1 (w). 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).(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

Solution :-

1). The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A hydrocarbon exhibits no bands above 3000 but gives weak absorption at 2200 cm^-1.

Solution 2200 cm-1 is the characteristics peak for the internal alkyne

So the functional group would be internal alkyne

Or the nitrile group also gives the peak at 2200 cm- 1

So it can be nitrile or internal alkyne

2) The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A compound containing C, H, and O exhibits strong, broad absorption band at 3430 cm^-1, a sharp band at 3300, and a band at 2200 cm^-1 (m).

Solution :-   

2200 cm-1 is alkyne peak it also gives peak at 3300 and 3430 cm-1 means its terminal alkyne and alcoholic OH

So the functional groups are

Terminal alkyne and alcohol

3) The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A C6 hydrocarbon exhibits bands between 3000-3100 (w), 2850-2960 (m), and at 1650 cm^-1 (w).

Solution

Peak at 1650 cm-1 is for the C=C bonds

C6 hydrocarbon means it may be aromatic ring that is arene

2850 – 2960 cm-1 is for the C-H stretch in alkane

3100 – 3000 cm-1 is for the C-H in alkene that is unsaturation

So the functional groups are

Arene , alkene , amide

1650 cm-1 can be for the amide

So amide is also included.