To determine which compound contains an aldehyde functional group, we need to recognize the structural features associated with an aldehyde. An aldehyde has a carbonyl group (C=O) bonded to at least one hydrogen atom. The general formula for an aldehyde is R-CHO (where R is any carbon-containing group).
Let's examine each compound in the question:
1. [tex]\( \text{CH}_3-\overset{1}{\text{C}}- \text{H} \)[/tex]
This compound has the form of [tex]\( \text{R-CHO} \)[/tex] with R being [tex]\( \text{CH}_3 \)[/tex]. Here, the carbonyl group ( C=O) is bonded to one hydrogen atom and one [tex]\( \text{CH}_3 \)[/tex] group, fitting the criteria for an aldehyde.
2. [tex]\( \text{CH}_3- \text{CH}_2- \text{O} - \text{CH}_2- \text{CH}_3 \)[/tex]
This compound is an ether, characterized by an oxygen atom single-bonded to two alkyl groups. It does not have the carbonyl group (C=O) necessary for an aldehyde.
3. [tex]\( \text{CH}_3- \text{O} \cdot \text{CH}_2 \text{C} \text{H}_3 \)[/tex]
This compound also resembles an ether but might be problematic in terms of notation. Assuming it means[tex]\( \text{CH}_3- \text{O} - \text{CH}_2\text{C} \text{H}_3 \)[/tex], it is an ether where oxygen is single-bonded to two alkyl chains—this also does not fit the criteria for an aldehyde.
Thus, only the first compound ([tex]\( \text{CH}_3-\overset{1}{\text{C}}- \text{H} \)[/tex]) contains an aldehyde functional group.
