Zadanie 6f
Wzorowane na: Chemistry HL Paper 2, November 2022, pytanie 6(f). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Informacja do zadań 6a-6g.
2-Bromopentane can react with hydroxide ions, OH−, in a nucleophilic substitution reaction.
CH3CHBrCH2CH2CH3 + OH− → CH3CH(OH)CH2CH2CH3 + Br−
Polecenie
2-Bromopentane also reacts with cyanide ions, CN−, by the same mechanism as the one identified in (b). Explain this mechanism using curly arrows to represent the movement of electron pairs.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
curly arrow from the lone pair on the carbon atom of CN− to the carbon atom attached to bromine ✔
curly arrow from the C–Br bond to the bromine atom ✔
transition state showing the partially formed C···CN bond and the partially broken C···Br bond, with a negative charge, in square brackets ✔
If SN1 was selected in (b):
curly arrow from the C–Br bond to the bromine atom ✔
carbocation intermediate ✔
curly arrow from the lone pair on CN− to the carbocation ✔
Schemat punktowania
Award [3] for a complete mechanism consistent with the choice in (b). Cyanide attacks through carbon, so the arrow must start on the carbon of CN−. Allow ECF from (b).