Final answer:
To determine the UN/DBE for a compound, a complete molecular formula is needed; IR spectra can help identify or exclude functional groups by characteristic peaks, but without the actual spectrum or full molecular formula details, it's not possible to specify which functional groups are definitely not present in compound E.
Step-by-step explanation:
The unsaturation number (UN) or double-bond equivalent (DBE) provides insight into the number of rings and multiple bonds in a compound. To calculate the UN/DBE for compound E with molecular formula CO3, we would use the formula for degree of unsaturation. However, without the specific number of carbons (C) and hydrogens (H) in the molecular formula, this cannot be computed. The Unsaturation Number (UN) or Double-Bond Equivalent (DBE) can be calculated using the formula:
UN = (2C + 2 + N - X)/2
Where C is the number of carbon atoms
N is the number of nitrogen atoms
X is the number of halogen, sulfur, or phosphorus atoms
In the case of compound E with the molecular formula C,H,O3, there are no nitrogen, halogen, sulfur, or phosphorus atoms, so the equation simplifies to:
UN = (2(1) + 2 - 0)/2 = 2
The UN/DBE for compound E is 2.
With the IR spectrum, one can identify functional groups based on characteristic absorption peaks. For example, an ester would typically show a strong absorption around 1750 cm^-1, while a broad peak around 3200-3600 cm^-1 is indicative of an alcohol. An alkyne would show absorptions near 2100-2250 cm^-1. A benzene ring is typically identified by absorptions around 1600 cm^-1, 1500 cm^-1, and 1450 cm^-1. Carboxylic acids show a broad peak due to OH stretching above 2500 cm^-1 in combination with a strong peak around 1700 cm^-1. Without the IR spectrum, we cannot definitively conclude which functional groups are not present.