Zadanie 38
Wzorowane na: Chemistry HL Paper 1, November 2022, pytanie 38. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
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Polecenie
What information about pentan-2-one, CH3COCH2CH2CH3, can be obtained from mass spectrometry (MS), infrared (IR) spectroscopy and 1H NMR spectroscopy?
A. MS: the compound contains a carbonyl group; IR: the molar mass is 86 g mol−1; NMR: the carbonyl group is on carbon 2, not carbon 3
B. MS: the molar mass is 86 g mol−1; IR: the carbonyl group is on carbon 2, not carbon 3; NMR: the compound contains a carbonyl group
C. MS: the molar mass is 86 g mol−1; IR: the compound contains a carbonyl group; NMR: the carbonyl group is on carbon 2, not carbon 3
D. MS: the carbonyl group is on carbon 2, not carbon 3; IR: the compound contains a carbonyl group; NMR: the molar mass is 86 g mol−1
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
C ✔
«the molecular ion peak in MS gives the molar mass (M = 86 g mol−1); the strong C=O absorption near 1700 cm−1 in IR shows a carbonyl group; the number of environments and the integration in 1H NMR show the position of the carbonyl group (four signals for pentan-2-one, two for pentan-3-one). IR cannot show position and NMR cannot give the molar mass»
Schemat punktowania
One mark for the correct option.