Which compound matches the IR spectrum?
cyclohexane
trans-4-octene
3-hexanol
Odipropyl ether
1-methylcyclopentene
1-hexen-3-ol
1,5-hexadiene
The Correct Answer and Explanation is :
To match an IR spectrum with a compound, key functional groups and bonds present in the compound need to be identified. Let’s break down each compound in the list and analyze what functional groups would show up in their respective IR spectra.
- Cyclohexane: Cyclohexane is a simple saturated alkane, meaning its IR spectrum would show a characteristic C-H stretching band around 2850-2960 cm⁻¹ (for C-H bonds) and C-H bending at around 1465 cm⁻¹. There would be no significant functional groups like C=C or O-H.
- trans-4-octene: This compound is an alkene. The IR spectrum would show:
- C-H stretching around 2850-2960 cm⁻¹.
- C=C stretching around 1600 cm⁻¹.
- C-H bending around 900-1000 cm⁻¹ for the trans-configuration.
- 3-hexanol: This is an alcohol. Its IR spectrum would show:
- O-H stretching around 3200-3550 cm⁻¹ (broad band).
- C-H stretching around 2850-2960 cm⁻¹.
- C-O stretching around 1050-1150 cm⁻¹.
- Dipropyl ether: As an ether, dipropyl ether’s IR spectrum would show:
- C-H stretching around 2850-2960 cm⁻¹.
- C-O-C stretching around 1050-1150 cm⁻¹.
- No O-H stretch, since it’s not an alcohol.
- 1-methylcyclopentene: This compound has an alkene group. The IR spectrum would show:
- C-H stretching around 2850-2960 cm⁻¹.
- C=C stretching around 1600 cm⁻¹.
- C-H bending near 1000 cm⁻¹ for the alkene group.
- 1-hexen-3-ol: This compound has both an alcohol and an alkene. The IR spectrum would show:
- O-H stretching around 3200-3550 cm⁻¹ (broad).
- C-H stretching around 2850-2960 cm⁻¹.
- C=C stretching around 1600 cm⁻¹.
- C-O stretching around 1050-1150 cm⁻¹.
- 1,5-hexadiene: This is a diene, and its IR spectrum would show:
- C-H stretching around 2850-2960 cm⁻¹.
- C=C stretching around 1600 cm⁻¹.
- C-H bending near 1000 cm⁻¹.
Correct Answer: 3-hexanol
- The O-H stretching in the range of 3200-3550 cm⁻¹ is a strong indicator of an alcohol.
- C-H stretching and C-O stretching also appear in the expected regions.
Let’s generate the IR spectrum image for 3-hexanol.
Here is an illustration of the infrared (IR) spectrum for 3-hexanol. The key features, such as the broad O-H stretching around 3200-3550 cm⁻¹ and the C-O stretching around 1050-1150 cm⁻¹, are clearly visible.
