Questions: Multiple Select Question Select all that apply Which of the following are the expected IR absorptions for an alkene, which would help to distinguish its IR spectrum from that of an alkane or al that apply. strong peak at 3000 - 2850 cm^-1 medium peak at 3150-3000 cm^-1 strong peak at 1800 cm^-1 medium peak at 1050 cm^-1

Multiple Select Question
Select all that apply
Which of the following are the expected IR absorptions for an alkene, which would help to distinguish its IR spectrum from that of an alkane or al that apply.
strong peak at 3000 - 2850 cm^-1
medium peak at 3150-3000 cm^-1
strong peak at 1800 cm^-1
medium peak at 1050 cm^-1

Transcript text: Multiple Select Question Select all that apply Which of the following are the expected IR absorptions for an alkene, which would help to distinguish its IR spectrum from that of an alkane or al that apply. strong peak at $3000 \cdot 2850 \mathrm{~cm}^{-1}$ medium peak at $3150-3000 \mathrm{~cm}^{-1}$ strong peak at $1800 \mathrm{~cm}^{-1}$ medium peak at $1050 \mathrm{~cm}^{-1}$

Solution

Solution Steps

Step 1: Analyze the given information

The question mentions several peaks in an infrared (IR) spectrum. IR spectra are used to identify functional groups in molecules based on the absorption of infrared light at specific wavenumbers.

Step 2: Interpret the peaks

Strong peak at 3000-2850 cm⁻¹: This range is characteristic of C-H stretching vibrations, typically associated with alkanes (single bonds between carbon and hydrogen).
Medium peak at 3150-3000 cm⁻¹: This indicates =C-H stretching vibrations, usually present in alkenes (double bonds between carbon atoms) or aromatic rings. Since it is of medium intensity, it suggests it is an aromatic =C-H stretch.
Strong peak at 1800 cm⁻¹: A strong peak around this region strongly suggests a C=O carbonyl stretch. This functional group is found in various compounds like ketones, aldehydes, carboxylic acids, esters, and amides.
Medium peak at 1650 cm⁻¹ (not explicitly mentioned): A missing piece of information that is usually present alongside other peaks, especially if an aromatic ring is mentioned, is the aromatic C=C stretch, which occurs as a medium peak around 1650 cm⁻¹.
Medium peak at 1050 cm⁻¹: This could be due to various C-O stretches or other bending vibrations, and without more information, it's harder to pinpoint its origin, although it fits within the range for a C-O stretch of an aromatic ether.

Step 3: Combine the information

The peaks suggest the molecule contains C-H bonds (both alkane and aromatic =C-H stretches), a C=O bond, likely an aromatic ring system (implied by the medium =C-H stretch and possibly medium C-O stretch) and possibly a C-O bond (depending on the exact identity of the peak at 1050 cm⁻¹). A likely molecule containing all these functionalities could be an aromatic ketone, potentially with an ether substituent.