CHAPTER 12 13 MS IR NMR Practice Exercises CHEM 2425 Dr Pahlavan Dr Cherif Dr Dessens 1 The mass spectrum an benzylhalide haloalkyl bezene is given a Identify the parent peak b Identify the base peak c Determine the possible structure for the compound d What is the molecular structure for the most stable cation fragment most intense peak 2 Give several types of spectroscopic data IR 1H NMR and MS of particular compounds What are they a C5H10O b C8H7N 1 c C7H14O 3 Each of the following compounds is characterized by a single 1H NMR spectrum that consists of only a single peak having the chemical shift Identify each compound a C8H18 0 9 ppm b C4H9Br 1 8 ppm 4 Each of the following compounds is characterized by a single 1H NMR spectrum that consists of two peaks both singlets having the chemical shifts indicated Identify each compound a C6H8 2 7 ppm 4H and 5 6 ppm 4H b C6H10O2 2 2 ppm 6H and 2 7 ppm 4H 2 5 Deduce the structure of each of the following compounds in the basis of their 1H NMR spectral and molecular formula a C8H10 1 2 ppm triplet 3H 2 6 ppm quarter 2 H 7 1 ppm broad singlet 5H b C4H6Cl4 3 9 ppm doublet 4H 4 6 ppm triplet 2H 6 How many different types of hydrogens in different environments are there in the following compounds a 1 chloropropane d 2 chloropropene b 2 2 dimethylpropane e cis 1 3 dichloropropene c phenol d 2 chloropropane f E 1 3 dibromopropene 7 An unknown compound having molecular formula C4H8O exhibits the following IR and H NMR data Give the structure of this compound based on these spectra indicating the salient features of each spectrum IR 1710 cm 1 strong single band 1 H NMR 1 0 broad t 3H 2 1 broad s 3H 2 5 qt 2H 8 Propose a structure that is consistent with the following spectral data MS M at m z 73 IR 3350 cm 1 weak single band 1 H NMR 1 05 broad s 1 H 1 15 t 6 H 2 65 qt 4H 9 The mass spectrum of a hydrocarbon shows a molecular ion at m z 182 and the 1 H NMR spectrum has two signals 2 9 singlet 4 H 7 2 singlet 10 H Propose a structure for this compound 10 For each compound below tell how many types of nonequivalent protons there are Br a CH3 O Br CH3 b c CH3 3 C C CH2CH3 N CH2CH3 11 Cyclohexane and 2 hexene both have molecular formula C6H10 How would you use infrared spectroscopy to distinguish between the two compounds Please explain your answer 3 12 The molecular formula for an unknown compound is CxHyO MW 60 Data for the 1H NMR infrared and mass spectra for this compound are shown below Using the spectral and analytical information provided determine the structure for this compound 4 13 The molecular formula for an unknown compound is CxHyO Data for the 1H NMR infrared and mass spectra for this compound are shown below Using the spectral and analytical information provided determine the structure for this compound 5 14 The molecular formula for an unknown compound is CxHyO3 Data for the 1H NMR infrared and mass spectra for this compound are shown below Using the spectral and analytical information provided determine the structure for this compound 6 15 The molecular formula for an unknown compound is CxHyO2 Data for the 1H NMR infrared and mass spectra for this compound are shown below Using the spectral and analytical information provided determine the structure for this compound 7 ANSWERS CHAPTER 12 13 MS IR NMR Practice Exercises CHEM 2425 Dr Pahlavan Dr Cherif Dr Dessens 1 a m e 172 b m e 91 c d 2 a C5H10O D U 5 10 2 1 1 db carbonyl group C O 3 Pentanone or Diethylpentane b C8H7N D U 7 7 2 1 2 1 6 1 benzene ring 1 tb Benzylhydride c C7H14O D U 7 14 2 1 carbonyl group C O 2 Heptanone or pentylmethyl ketone 3 a C8H18 D U 8 18 2 1 0 single bond CH3 3 C C CH3 3 b C4H9Br D U 4 9 2 1 2 1 0 single bond CH3 3 C Br a 2 2 3 3 Tetramethyl butane b t Butyl bromide 4 a C6H8 D U 6 8 2 1 3 two types protons b C6H10Br2 D U 6 10 2 1 2 two double bonds a 1 4 Cyclohexadiene b 2 5 Heptadiene 5 a C8H10 b C4H6 Cl4 D U 8 10 2 1 4 Benzene ring D U 4 6 2 4 2 1 0 single bond CH2Cl CHCl CH Cl CH2Cl 6 a CH3 CH2 CH2 Cl 3 types H s b CH3 C CH3 2 CH3 1 types H s c 4 types H s d CH3 CHCl CH3 2 types H s e CH3 CCl CH2 2 types H s 8 f 3 types H s g 3 types H s 7 C4H8O D U 4 8 2 1 1 db bond carbonyl group C O 1710 cm 1 2 Butanone or Ethylmethyl ketone m z 77 77 14 59 59 12 6 C 10 H 1 N C4H10N D U 4 10 2 1 0 IR 3350 cm 1 amine C N CH3 CH2 NH CH2 CH3 Diethylamine 9 m e 182 182 12 14 C 14 H C14H14 D U 14 14 2 1 8 2 benzene ring 8 MS Diethylbenzene 10 a 2 b 2 c 11 Use IR IR cyclohexane 3000 3100 cm 1 and IR 2 Hexene 1640 1680 cm 1 12 CxHyO MW 60 60 16 44 44 12 3 C 8H 1 O C3H8O D U 3 8 2 1 0 single bond IR 3100 cm 1 OH group CH3 CHOH CH3 2 propanol isopropyl alcohol isopropanol 13 CxHyO MW 86 86 16 70 70 12 5 C 10H 1 O C5H10O D U 5 10 2 1 1 db carbonyl group C O 1710 cm 1 3 Methyl 2 butanone or isopropylmethyl ketone 14 CxHyO3 MW 130 130 48 82 82 12 6 C 10H 3 O C3H8O3 D U 6 10 2 1 2 2 dbs 2 C O 15 CxHyO2 MW 138 138 32 106 106 12 8 C 10H 2 O C8H10O2 D U 8 10 2 1 4 Benzene ring 9 10