Zadanie 4d
Wzorowane na: Chemistry HL Paper 2, May 2026, TZ3, pytanie 4(d). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Informacja do zadań 4a-4f.
Organic compounds are made from many different starting materials and by a variety of reactions, and some of them are used as fuels.
Polecenie
Ethane, C2H6, reacts with chlorine, Cl2, to produce chloroethane, C2H5Cl.
(i) Outline why the reaction does not start unless the mixture is exposed to ultraviolet light.
(ii) Deduce two propagation steps and one termination step for this mechanism.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
(i) the light supplies the energy to break the Cl–Cl bond «homolytic fission»
OR
it produces chlorine radicals, Cl ∙ ✔
(ii) Propagation:
C2H6 + Cl ∙ → C2H5 ∙ + HCl ✔
C2H5 ∙ + Cl2 → C2H5Cl + Cl ∙ ✔
Termination: any one of:
Cl ∙ + Cl ∙ → Cl2
OR
C2H5 ∙ + Cl ∙ → C2H5Cl
OR
C2H5 ∙ + C2H5 ∙ → C4H10 ✔
Schemat punktowania
(i) [1]. (ii) [1] each for the two propagation steps and for one termination step. Penalize missing radical dots only once; do not penalize the position of the dot on a species.