Zadanie 39
Wzorowane na: Chemistry HL Paper 1A, May 2026, TZ3, pytanie 39. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
Which statements about the reaction of hydrogen bromide with 2-methylpropene are correct?
I. A tertiary carbocation is formed as an intermediate.
II. The major product is a primary halogenoalkane.
III. The first step of the mechanism is attack of an electrophile on the C=C bond.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
B ✔
«H+ attacks the double bond to give the more stable tertiary carbocation (CH3)3C+, which is attacked by Br− to give 2-bromo-2-methylpropane, a tertiary halogenoalkane; I and III are correct, II is not»
Schemat punktowania
1 mark for the correct option.
Komentarz
The major product comes from the more stable carbocation, here tertiary rather than primary.