## Step 1: Analyze the Spectral Data (IR and CNMR) For each pair, compare the given IR and CNMR values: - **Carbonyl IR (cm⁻¹):** - **Amides:** ~168–170 cm⁻¹ - **Esters:** ~1735–175 cm⁻¹ - **Acid Chlorides:** ~177–180 cm⁻¹ - **Aldehydes/Ketones:** ~170–1725 cm⁻¹ - **Carbonyl CNMR (ppm):** - **Amides:** ~165–180 ppm - **Esters:** ~165–185 ppm - **Acid Chlorides:** ~160–170 ppm - **Aldehydes/Ketones:** ~190–210 ppm **Explanation:** Matching the IR and CNMR data allows you to determine the correct functional group and thus the correct isomer. --- ## Step 2: Match Each Structure to the Correct Isomer Let's go pair by pair: ### Pair 1 (Top Left) - **Wrong structure:** 6-membered ring with amide - **IR:** 1685 cm⁻¹ - **CNMR:** 200 ppm **Correct Isomer:** A structure with a carbonyl group as a ketone (because 200 ppm in CNMR is typical for aldehydes/ketones, not amides). **Explanation:** The IR matches an amide, but the CNMR is too high for an amide; it's correct for a ketone. **Final Isomer:** Cyclohexanone --- ### Pair 2 (Top Center) - **Wrong structure:** 6-membered ring with ester - **IR:** 1745 cm⁻¹ - **CNMR:** 210 ppm **Correct Isomer:** A structure with a carbonyl as an aldehyde, since 210 ppm is typical for aldehydes. **Explanation:** IR fits an ester, but CNMR indicates an aldehyde. **Final Isomer:** Cyclohexanecarbaldehyde --- ### Pair 3 (Top Right) - **Wrong structure:** 4-membered ring with two double bonds (enone) - **IR:** 1685 cm⁻¹ - **CNMR:** 190 ppm **Correct Isomer:** A cyclobutanone (4-membered ring ketone), since the IR matches a ketone and CNMR is also consistent with a ketone. **Explanation:** IR and CNMR both support a simple ketone. **Final Isomer:** Cyclobutanone --- ### Pair 4 (Bottom Left) - **Wrong structure:** 4-membered ring with a Cl and carbonyl (acid chloride) - **IR:** 1775 cm⁻¹ - **CNMR:** 160 ppm **Correct Isomer:** A 4-membered ring ester (lactone), because the IR and CNMR are a bit lower than acid chloride but fit an ester. **Explanation:** IR and CNMR are on the lower range, consistent with a strained ring ester. **Final Isomer:** Beta-propiolactone (4-membered ring lactone) --- ### Pair 5 (Bottom Center) - **Wrong structure:** 6-membered ring with amide - **IR:** 1715 cm⁻¹ - **CNMR:** 170 ppm **Correct Isomer:** A 6-membered ring ester, as both IR and CNMR match an ester. **Explanation:** Both values match an ester rather than an amide. **Final Isomer:** Cyclohexanone --- ### Pair 6 (Bottom Right) - **Wrong structure:** Acetone (dimethyl ketone) - **IR:** 1715 cm⁻¹ - **CNMR:** 175 ppm **Correct Isomer:** Methyl acetate (an ester), since the IR and CNMR better match an ester. **Explanation:** IR and CNMR are high for a simple ketone, more typical for ester. **Final Isomer:** Methyl acetate --- ## **Final Answers Summary** 1. **Cyclohexanone** (6-membered ring ketone) 2. **Cyclohexanecarbaldehyde** (6-membered ring aldehyde) 3. **Cyclobutanone** (4-membered ring ketone) 4. **Beta-propiolactone** (4-membered ring lactone) 5. **Cyclohexanone** (repeat: 6-membered ring ketone) 6. **Methyl acetate** (ester)

# Correct Isomer Identification Based on Spectral Data ## Step 1: Analyze the Spectral Data (IR and CNMR) For each pair, we will compare the provided Infrared (IR) and Carbon Nuclear Magnetic Resonance (CNMR) values to determine the correct isomer. ### IR and CNMR Reference Ranges - **Carbonyl IR (cm⁻¹):** - Amides: ~168–170 cm⁻¹ - Esters: ~1735–1750 cm⁻¹ - Acid Chlorides: ~177–180 cm⁻¹ - Aldehydes/Ketones: ~170–1725 cm⁻¹ - **Carbonyl CNMR (ppm):** - Amides: ~165–180 ppm - Esters: ~165–185 ppm - Acid Chlorides: ~160–170 ppm - Aldehydes/Ketones: ~190–210 ppm **Explanation:** Matching the IR and CNMR values helps identify the functional group and thus the correct isomer for each pair. --- ## Step 2: Match Each Structure to the Correct Isomer ### Pair 1 (Top Left) - **Wrong Structure:** 6-membered ring with amide - **IR:** 1685 cm⁻¹ - **CNMR:** 200 ppm **Correct Isomer:** Cyclohexanone **Explanation:** The IR suggests an amide, but the CNMR (200 ppm) indicates a ketone (common for aldehydes/ketones). Hence, a ketone is appropriate here. --- ### Pair 2 (Top Center) - **Wrong Structure:** 6-membered ring with ester - **IR:** 1748 cm⁻¹ - **CNMR:** 210 ppm **Correct Isomer:** Cyclohexanecarbaldehyde **Explanation:** The IR value fits an ester, but the CNMR (210 ppm) is typical for aldehydes. Therefore, the correct isomer is an aldehyde. --- ### Pair 3 (Top Right) - **Wrong Structure:** 4-membered ring with two double bonds (enone) - **IR:** 1685 cm⁻¹ - **CNMR:** 190 ppm **Correct Isomer:** Cyclobutanone **Explanation:** Both IR and CNMR align well with a simple ketone, making cyclobutanone the correct isomer. --- ### Pair 4 (Bottom Left) - **Wrong Structure:** 4-membered ring with a Cl and carbonyl (acid chloride) - **IR:** 1775 cm⁻¹ - **CNMR:** 160 ppm **Correct Isomer:** Beta-propiolactone (4-membered ring lactone) **Explanation:** The IR and CNMR values suggest a lower range consistent with a strained ring ester rather than an acid chloride. --- ### Pair 5 (Bottom Center) - **Wrong Structure:** 6-membered ring with amide - **IR:** 1715 cm⁻¹ - **CNMR:** 170 ppm **Correct Isomer:** Cyclohexyl acetate (6-membered ring ester) **Explanation:** The IR and CNMR values match an ester, making it the correct choice. --- ### Pair 6 (Bottom Right) - **Wrong Structure:** Acetone (dimethyl ketone) - **IR:** 1715 cm⁻¹ - **CNMR:** 175 ppm **Correct Isomer:** Methyl acetate **Explanation:** The values are more characteristic of an ester, not a simple ketone, leading us to identify methyl acetate. --- ## Final Answers Summary 1. **Cyclohexanone** (6-membered ring ketone) 2. **Cyclohexanecarbaldehyde** (6-membered ring aldehyde) 3. **Cyclobutanone** (4-membered ring ketone) 4. **Beta-propiolactone** (4-membered ring lactone) 5. **Cyclohexyl acetate** (6-membered ring ester) 6. **Methyl acetate** (ester)