5. Redox Titrations Flashcards
redox titrations find out
how much oxidizing agent is needed to
exactly react with a quantity of reducing agent
(or vice versa)
transition elements are used as
oxidising and reducing agents
why are transition elements used as oxidising and reducing agents
good at changing oxidation state (readily give out/receive electrons)
change in oxidation state = change color (easy to spot when reaction is finished)
rule of titration
add known concentration to substance of unknown concentration
titration steps
finding out how many manganate (VII) ions (MnO4-) are needed to react with reducing agent
- measure quantity of reducing agent e.g Fe2+(aq) ions using a pipette, and put in conical flask
- add some dilute sulfuric acid in excess to conical flask. (ensures plenty of H+ to allow oxidising agent to be reduced)
- gradually add aqueous MnO4- (oxidising agent) to reducing agent using burette, swirling conical flask
- stop when mixture in flask just becomes tainted with colour of MnO4- and record volume of oxidising agent added
- run a few titrations then calculate mean volume of MnO4-
how to make colour changes easier to spot
doing reaction in front of a white surface
oxidising agent _____ electrons and gets ______
accepts
reduced
reducing agent _____ electrons and gets _____
donates
oxidised