Manganate(VII) Redox Titrations (OCR A-Level Chemistry A): Flashcards

Determine concentration of reducing agents

$\text{MnO}_4^-$ changes colour; no separate indicator needed

First permanent pale pink colour

$\text{Cl}^-$ ions oxidised by $\text{MnO}_4^-$, giving wrong results

Read from top of meniscus (consistently for initial & final)

5 electrons needed

1:5 (1 mol $\text{MnO}_4^-$ reacts with 5 mol $\text{Fe}^{2+}$)

At least 2 titres within ±0.10 cm³ of each other

$\text{MnO}_4^-$ deep purple; $\text{Mn}^{2+}$ very pale pink

$n = c \times \frac{V}{1000}$ (V in cm³)