Table of contents

1. Chemical Measurements1h 50m
2. Tools of the Trade1h 17m
3. Experimental Error1h 52m
4 & 5. Statistics, Quality Assurance and Calibration Methods1h 57m
6. Chemical Equilibrium3h 41m
7. Activity and the Systematic Treatment of Equilibrium1h 0m
8. Monoprotic Acid-Base Equilibria1h 53m
9. Polyprotic Acid-Base Equilibria2h 17m
10. Acid-Base Titrations2h 37m
11. EDTA Titrations1h 34m
12. Advanced Topics in Equilibrium1h 16m
13. Fundamentals of Electrochemistry2h 19m
14. Electrodes and Potentiometry41m
15. Redox Titrations1h 14m
16. Electroanalytical Techniques57m
17. Fundamentals of Spectrophotometry50m

1. Chemical Measurements

Chemical Concentrations

Analytical Chemistry

1. Chemical Measurements

Chemical Concentrations

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Multiple Choice

Which region of the infrared (IR) spectrum (in cm⁻¹) is most commonly used to identify the presence of a carbonyl (C=O) functional group in a molecule with the molecular formula C4H8O2?

1000–1300 cm⁻¹

1700–1750 cm⁻¹

3200–3600 cm⁻¹

2100–2260 cm⁻¹

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Verified step by step guidance

Step 1: Understand the problem. The question asks which region of the infrared (IR) spectrum is most commonly used to identify the presence of a carbonyl (C=O) functional group in a molecule with the molecular formula C4H8O2. Infrared spectroscopy is a technique used to identify functional groups based on their characteristic absorption frequencies.

Step 2: Recall the characteristic IR absorption range for a carbonyl (C=O) functional group. Carbonyl groups typically exhibit a strong and sharp absorption band in the range of 1700–1750 cm⁻¹ due to the stretching vibration of the C=O bond.

Step 3: Analyze the given options. The options provided are: 1000–1300 cm⁻¹, 1700–1750 cm⁻¹, 3200–3600 cm⁻¹, and 2100–2260 cm⁻¹. Compare these ranges to the known absorption range for carbonyl groups.

Step 4: Eliminate irrelevant options. The range 1000–1300 cm⁻¹ is typically associated with C-O stretching vibrations, not C=O. The range 3200–3600 cm⁻¹ corresponds to O-H stretching vibrations, and 2100–2260 cm⁻¹ is associated with C≡C or C≡N triple bonds. Therefore, these ranges are not relevant for identifying a carbonyl group.

Step 5: Confirm the correct range. The range 1700–1750 cm⁻¹ is the most commonly used region to identify the presence of a carbonyl (C=O) functional group in IR spectroscopy. This is due to the strong and distinct absorption caused by the stretching vibration of the C=O bond.