Zadanie 5d
Wzorowane na: Chemistry HL Paper 2, May 2024, TZ2, pytanie 5(d). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
Propenal can be oxidised to compound G. G produces bubbles of gas when it is added to aqueous sodium hydrogencarbonate. The mass spectrum of G is shown.
Deduce what G is and give two reasons, based on the mass spectrum.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
CH2=CHCOOH / propenoic acid ✔
[2 max] for two of:
the peak at m/z 72 is the molecular ion, [C3H4O2]+ «M = 72 g mol−1» ✔
the peak at m/z 55 arises by loss of ⋅ OH (17), leaving CH2=CHCO+ ✔
the peak at m/z 45 is COOH+ «loss of CH2=CH ⋅, 27» ✔
the peak at m/z 27 is CH2=CH+ «loss of ⋅ COOH, 45» ✔
Schemat punktowania
M1: the identity; M2 and M3: two correct peak assignments from the list (the m/z value must be linked to a fragment or to the molecular ion). Section 22 of the data booklet lists the fragments lost.