Questions: Pair of Functional Groups Similar IR Expected for: Differentiating IR Expected for: aldehyde carboxylic acid C=O stretch 1700 cm^-1 Very broad H-O stretch for acid only at 3600-2500 cm^-1 alcohol ether, both with 3 carbons alkane alkyne, both with 3 carbons alkane alcohol, both with 3 carbons ester ketone

Solution Steps

Alcohols and ethers both contain C-O bonds, which typically show a C-O stretch in the IR spectrum. This stretch is usually observed around \(1050-1150 \, \text{cm}^{-1}\).

Alcohols have an O-H group, which shows a broad O-H stretch in the IR spectrum, typically observed around \(3200-3550 \, \text{cm}^{-1}\). Ethers do not have this feature.

Both alkanes and alkynes contain C-H bonds, which show C-H stretching vibrations. For alkanes, this is typically observed around \(2850-2960 \, \text{cm}^{-1}\).

Alkynes have a C≡C triple bond, which shows a sharp peak around \(2100-2260 \, \text{cm}^{-1}\). Alkanes do not have this feature.

Both alkanes and alcohols contain C-H bonds, which show C-H stretching vibrations around \(2850-2960 \, \text{cm}^{-1}\).

Alcohols have an O-H group, which shows a broad O-H stretch around \(3200-3550 \, \text{cm}^{-1}\). Alkanes do not have this feature.

Both esters and ketones contain a C=O bond, which shows a C=O stretch in the IR spectrum. This stretch is typically observed around \(1700-1750 \, \text{cm}^{-1}\).

Esters have an additional C-O stretch, which is typically observed around \(1050-1300 \, \text{cm}^{-1}\). Ketones do not have this feature.

Final Answer