Zadanie 3d
Wzorowane na: Chemistry HL Paper 1B, May 2026, TZ2, 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-3f.
A titration was performed to find the concentration of iron(II) ions in a solution made from iron tablets. Portions of 25.00 cm3 of the iron(II) solution were acidified with excess dilute sulfuric acid and titrated with potassium manganate(VII) solution, which acts as its own indicator.
MnO4−(aq) + 5 Fe2+(aq) + 8 H+(aq) → Mn2+(aq) + 5 Fe3+(aq) + 4 H2O(l)
A standard 0.0200 mol dm−3 potassium manganate(VII) solution was used in a preliminary trial. The volume of titrant required was less than 5 cm3, so the standard solution was diluted before the main titrations.
Polecenie
The titration was carried out using a burette, a volumetric pipette and a conical flask.
State which of the three items should be rinsed with the solution it will hold, and which only with distilled water.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
rinsed with the solution: burette AND pipette ✔
rinsed with distilled water only: conical flask ✔
Schemat punktowania
M1: both burette and pipette, and no other item. M2: the conical flask. Rinsing the flask with the sample would change the amount of iron(II) in it.