3-methyl-1-butanol IR spectrum labeled (show characteristic peaks, bond types, functional groups
The Correct Answer and Explanation is:
3-Methyl-1-butanol is an alcohol with the chemical formula C5H12O, and its IR spectrum can provide valuable information about its functional groups and molecular structure. Below is an analysis of the typical IR peaks and their corresponding bond types and functional groups:
1. Broad O-H Stretch (3200-3550 cm⁻¹)
- Bond Type: O-H stretch
- Functional Group: Alcohol group
- The broad, strong absorption between 3200-3550 cm⁻¹ is characteristic of the O-H stretch in alcohols. The broadness is due to hydrogen bonding, which is common in alcohols. This band is one of the most prominent in the IR spectrum of alcohols.
2. C-H Stretch (2850-2960 cm⁻¹)
- Bond Type: C-H stretch
- Functional Group: Alkyl group
- The peaks observed in the region 2850-2960 cm⁻¹ correspond to the C-H stretching vibrations in the methyl (–CH3) and methylene (–CH2) groups. These are typical of aliphatic hydrocarbons and appear as moderate to strong peaks.
3. C-H Bending (1465-1450 cm⁻¹)
- Bond Type: C-H bending
- Functional Group: Alkyl group
- The C-H bending or scissoring absorption in the region 1465-1450 cm⁻¹ is due to the methyl groups (–CH3). This bending vibration is characteristic of the presence of alkyl groups and is often seen in the IR spectra of straight-chain and branched alkanes.
4. C-O Stretch (1050-1150 cm⁻¹)
- Bond Type: C-O stretch
- Functional Group: Alcohol group
- The absorption around 1050-1150 cm⁻¹ corresponds to the C-O stretch vibration. This is typical for alcohols and is usually a moderate to strong peak.
5. C-C Stretch (800-1100 cm⁻¹)
- Bond Type: C-C stretch
- Functional Group: Alkane backbone
- A C-C stretch occurs at 800-1100 cm⁻¹, which is typical of the carbon-carbon single bonds in alkanes.
Summary:
The IR spectrum of 3-methyl-1-butanol will show a broad O-H stretch around 3200-3550 cm⁻¹ (indicative of the alcohol group), C-H stretches in the 2850-2960 cm⁻¹ range (from methyl and methylene groups), C-H bending in the 1465-1450 cm⁻¹ range, a C-O stretch around 1050-1150 cm⁻¹, and C-C stretches between 800-1100 cm⁻¹. These peaks are key to identifying the molecular structure and functional groups present in 3-methyl-1-butanol.
