Zadanie 3d
Wzorowane na: Chemistry SL Paper 2, May 2026, TZ3, pytanie 3(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 3a-3d.
Metals and their compounds are used in construction and in batteries.
Polecenie
Iron and nickel can be used to design a voltaic cell.
Fe(s) + Ni2+(aq) → Fe2+(aq) + Ni(s)
(i) Annotate the diagram with the appropriate electrodes, electrolyte solutions and the direction of electron flow.
(ii) The redox reactions in some voltaic cells can be reversed. Explain how the cell in part (i) would be recharged.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
(i) anode: iron electrode in Fe2+(aq) solution AND cathode: nickel electrode in Ni2+(aq) solution «all four species correctly placed» ✔
arrow in the external circuit from the anode / iron electrode to the cathode / nickel electrode ✔
(ii) the voltmeter is replaced by an external battery / power supply ✔
the supply forces electrons to flow in the opposite direction, from the nickel electrode to the iron electrode / reverses the current ✔
Fe2+ is reduced to Fe so the iron electrode regains mass
OR
Ni is oxidized so the concentration of Ni2+ is restored ✔
Schemat punktowania
(i) M1: all four species (two electrodes and two solutions) correct, otherwise no mark; M2: electron-flow arrow from anode to cathode through the wire, not through the salt bridge. (ii) M1: a power supply replaces the voltmeter; M2: the direction of electron flow is reversed; M3: the original reactant is regenerated (Fe rebuilt or Ni2+ restored). Diagrams are accepted for M1 and M2.