Zadanie 2c
Wzorowane na: Chemistry HL Paper 3, May 2023, TZ1, pytanie 2(c). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
A steel bolt is to be coated with a thin layer of a metal by electroplating, using an aqueous solution of a salt of the coating metal as the electrolyte. Deduce one metal that could be deposited on the bolt with high efficiency. Use section 19 of the data booklet.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
any one of: copper/Cu OR silver/Ag ✔
«accept nickel/Ni, tin/Sn or lead/Pb»
«E⦵ of the metal ion is positive or only slightly negative, so the metal ion is reduced at the cathode in preference to water, and little hydrogen forms»
Schemat punktowania
Award [1] for one suitable metal. Do not accept metals with a clearly negative E⦵, such as zinc, iron, aluminium, magnesium or sodium, because water is reduced instead of the metal ions.
Komentarz
Reduction of water competes at the cathode, so metals that sit well below the hydrogen half-cell in section 19 are plated with high efficiency.