MCQ on spectroscopic techniques Welcome to your MCQ on spectroscopic techniques Name Email NMR spectroscopy is useful for determining the type and number of _______ atoms in organic molecules. hydrogen carbon halogen hetero atoms What is the multiplicity of the methylene hydrogens of a carbon that is attached to a methyl group and to a methyl group and to a methoxy group? doublet singlet quartet triplet Each of the following compounds has a singlet in its 1H NMR spectrum. Which compound would have its singlet at the highest frequency? 1-bromo-2,2-dimethylpropane ethyl methyl ether ethyl-tert-butyl ether 1,2-dibromoethane Which of the following compounds would have the signal for its methylene hydrogens farthest downfield? ethyl chloride ethyl iodide ethyl bromide ethyl fluoride How many signals would you expect to see in the 1H NMR spectrum of chlorocyclobutane? 1 3 4 5 What is the multiplicity of the OH group of an alcohol in a solution that contains a trace amount of acid? doublet quintet quartet singlet How many signals would you expect to see in the 1H NMR spectrum of butane? 1 2 3 4 Which of the following will occur farthest downfield? the hydrogens of benzene the hydrogens of ethyne the hydrogens of dimethyl ether the hydrogens of H COH How many signals will vinyl chloride have in 1H NMR spectrum? 1 2 3 4 How many signals does 2,2,4-trimethylpentane have in its 1H NMR spectrum? 2 3 4 5 How many signals would you expect to see in the 1H NMR spectrum of 2-methylpropene? 2 3 4 5 Which of the following compounds is frequently used as an internal reference in 1H NMR spectroscopy? TNS DMF TMS DMSO Which of the following describes the 1H NMR spectrum of 1,2-dichloroethane? one doublet two triplets two doublets one singlet What is the multiplicity of the CH2, hydrogens in CH3OCH2CH2OCH3? a singlet a triplet a quartet a doublet What would be the splitting of the protons on the CH2 groups of butane? doublet sextet triplet singlet Only one signal is present in the PMR spectra of C₂H4, C3H6 C₂H6, C5H12 C8H18,C2H6 All A proton Hb is coupled to four equivalent protons Ha.The multiplicity and relative intensity of lines in the signal Hb is Doublet, 1: 4:9. Triplet 1: 4: 6 Quintet, 1: 4: 6: 4: 1 Quartet 1: 4: 6: 4:4. The compounds showing only a single peak in its PMR spectrum are: Acetone (I), Ether (II), Methyl acetate (III), Dibromoethane (IV), Chlorobromoethane (V). I, II, IV II, III, V I, III, V III, IV, V The aldehydic proton appears much downfield in the PMR because the aldehydic proton is Strongly shielded It lies in the deshielding zone of the carbonyl group It occurs at 10 8 ppm All The actual value of nuclear spin depends on Mass number Atomic number Both a and b Shielding effect The different types of energies associated with a molecule are __________ Electronic energy Vibrational energy Rotational energy All of the mentioned Please fill in the comment box below. Time's up
