11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy Chapter 13 Spectroscopy 1 Which of the following isomeric dibromopropanes has only a single peak in its C D 1 2 dibromopropane 2 2 dibromopropane proton NMR spectrum A 1 1 dibromopropane B 1 3 dibromopropane Ans D A 2 B 3 C 4 D 5 Ans C 2 How many different types sets of hydrogens are there in 2 2 dimethylpentane 3 Which of the following has only a single peak in its proton NMR spectrum 4 A compound is either cyclononane or cyclodecane Which of the following is the most A only I B only II C I and II D I II and III Ans C useful technique in identifying the compound A IR spectroscopy B mass spectrometry C proton NMR D C 13 NMR Ans B 5 Which of the following gives the furthest downfield shift from TMS in its proton NMR spectrum A CH C B CH N C CH O D CH F 3 4 Ans D 3 2 3 3 3 6 Which of the following gives the furthest downfield shift from TMS in its proton NMR spectrum A CCl B CHCl C CH Ans B 3 4 2Cl2 D CH 3Cl Page 199 about blank 1 19 11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy 7 How many different sets of equivalent protons are there for para xylene 1 4 dimethylbenzene A only 1 B two C three D four Ans B 8 How many different sets of equivalent protons are there in the following compound A three B four C five D six Ans A 9 What is the multiplicity of the methylene hydrogens indicated in the proton NMR of the following compound A doublet B triplet C quartet D pentet Ans D 10 What is the multiplicity of the methylene hydrogens indicated in the proton NMR of the following compound A singlet B doublet C triplet D quartet Ans A 11 What are the approximate intensities of the four lines in the quartet from the proton O Assume distortion of the quartet is minimal 3CH2 2 NMR of diethyl ether CH A 1 1 1 1 B 1 2 2 1 C 2 3 3 2 D 1 3 3 1 Ans D Page 200 about blank 2 19 11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy 12 Which compound below fits the following proton NMR data triplet 1 22 3H singlet 1 98 3H quartet 4 07 2H 13 The proton NMR of 1 1 dibromoethane would appear as a A A B B C C D D Ans B A B downfield doublet and upfield quartet downfield quartet and upfield doublet Ans B C downfield doublet and upfield triplet D downfield triplet and upfield doublet 14 The proton NMR spectrum of a compound gives singlets at 2 10 and 2 56 in a ratio of 3 2 respectively Which compound below is the best match for the spectrum A A B B C C D D Ans C Page 201 about blank 3 19 11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy 15 The proton NMR of a compound C ClO has the following peaks Which compound 8H9 below best fits the data broad singlet triplet 2 41 2H triplet 3 69 2H 7 02 2H doublet doublet 7 50 2H 2 41 1H A I B II C III D IV Ans C 16 The proton NMR spectrum of a compound C 3H6Cl2 has a pentet at 2 19 and a triplet at 3 72 in a 1 2 ratio respectively Which compound below best matches the data A A B B C C D D Ans B 17 A large doublet and a small septet pattern in H NMR is usually indicative of a n 1 A ethyl group B propyl group C isopropyl group D phenyl group Ans C 18 A triplet and quartet pattern in H NMR often indicates the presence of a n 1 A ethyl group B propyl group C isopropyl group D phenyl group Ans A Page 202 about blank 4 19 11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy 19 Which of the following describes the spin spin splitting of the indicated H in the H 1 NMR of the compound shown below A singlet B doublet of doublets C triplet D doublet of triplets Ans B 20 Identify the C Cl isomer given the following proton NMR data 4H9 1 04 6H doublet multiplet 1 95 1H doublet 3 35 2H A A B B C C D D Ans D 21 What region of the electromagnetic spectrum is used in nuclear magnetic resonance spectroscopy A radio wave B X ray C ultraviolet D microwave Ans A Page 203 about blank 5 19 11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy 22 Which of the compounds below fit the following C 13 NMR A para dichlorobenzene ortho dichlorobenzene B meta dichlorobenzene chlorobenzene Ans C 23 Identify which one of the following isomers of C 6H14 has the C 13 NMR below CH3CH CH CH CH CH 2 2 2 2 3 CH3 2 CHCH CH 3 2 CH3CH CH CH CH 2 2 3 2 CH3 CH C CH 2 3 3 A B Ans D C D C D Page 204 about blank 6 19 11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy 24 Which one of the following isomers of C 8H18 has only two peaks in its C NMR 13 A A B B C C D D Ans D 25 In infrared spectroscopy absorption of electromagnetic radiation results in transitions between energy levels A vibrational B electronic C rotational D nuclear Ans A 26 In proton NMR 1H 1 H spin spin splitting is common Why is there no comparable 13C 13C spin spin splitting in C 13 NMR A C 13 has a nuclear spin of zero The probability of two C 13 nuclei being next to each other in a compound is very low The coupling constant is very small too small to be observed 13C 13 There is decoupling techniques are used to suppress it C spin spin splitting but because of the complex splitting patterns B C D Ans B Page 205 about blank 7 19 11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy 27 What is the multiplicity of the indicated carbon in an off resonance decoupled C 13 NMR spectrum In off resonance decoupled spectra direct observed 13C 1 H coupling is A singlet B doublet C quartet D multiplet Ans B 28 Which one of the following compounds fits the C 13 NMR spectrum shown below A A B B C C D D Ans D Page 206 about blank 8 19 11 11 2024 13 12 Chapter 13 carey Chapter 13 Spectroscopy 29 A C 13 NMR spectrum of a compound C has five peaks Two peaks are in the 10 30 ppm region and the other three are in the 120 140 ppm area …