Redox Titrations

Question 1

What is an oxidising agent?

Answer 1

takes e- from the species being oxidised
it is the species being reduced

Question 2

What is the reducing agent?

Answer 2

add electrons to the species being reduced
it contains the species being oxidised

Question 3

What are the 2 redox titrations you need to know?

Answer 3

potassium manganate under acidic conds
sodium thiosulfate for the determination of iodine

Question 4

What is the colour of the end-point in the manganate titration?

Answer 4

colourless to pink

Question 5

What are the 2 reducing agents a manganate titration is used for analysis?

Answer 5

iron (2) ions
ethanedioic acid - (COOH)2

Question 6

What is oxidised in the sodium-thiosulfate titration?

Answer 6

thiosulfate ions - S2O3 2-

Question 7

What is reduced in the sodium-thiosulfate titration?

Answer 7

iodine - I2

Question 8

What colour-change idicates that you have added enough sodium thiosulfate to iodine in the conicle flask to be able to add starch?

Answer 8

a yellow brown to pale yellow

Question 9

What colour change indicates the end-point of the sodium-thiosulfate and iodine titration?

Answer 9

blue-black to pale straw colour

Question 10

What is the thiosulfate and iodine titration used for?

Answer 10

to determine the copper content of salt and alloys