Answer:
1. bond in the molecule on the right
Explanation:
CH3CH2-OH
The compound above is an alcohol due to the presence of the OH bond. The wave number of the C - O bond is given as; 1050-1150 cm^-1.
CH3CH__O
The compound above is an aldehyde due to the presence of the CHO bond. The wave number of the C = O bond is given as; 1740-1720 cm^-1
Comparing both bonds, the C = O bond absorbs at a higher wave number.
