redox

Question 1

potassium manganate(VII) formula

Answer 1

KMnO4

Question 2

potassium manganate manganese ox state

Answer 2

manganese ox state +7

Question 3

what happens to potassium manganate

Answer 3

reduced to Mn2+

Question 3

what happens to Fe

Answer 3

Oxidised from Fe2+ to Fe3+

Question 4

equation for Fe and KMnO4

Answer 4

Question 5

Explain colour change for Fe and KMnO4

Answer 5

[Mn(H2O)6] is pale pink usually looks colourless
MnO4- is purple
purple to colourless or persistent pale pink

Question 6

acidified potassium dichromate

Answer 6

K2Cr2O7

Question 7

Ox state of chromium in K2Cr2O7

Answer 7

6+

Question 8

what happens to K2Cr2O7

Answer 8

reduced to Cr3+

Question 9

What happens to zinc

Answer 9

oxidised from Zn to Zn2+

Question 10

dichromate (VI) formula

Answer 10

Cr2O7 2-

Question 11

Formula for KCr2O7 and Zn

Answer 11

Question 12

During titration, what goes in conical flask and burette? what else

Answer 12

normally reducing agent goes in conical flask whatever is oxidised
Add H2SO4 to ensure there are plenty of H+ ions to ensure the oxidising agent is reduced

Question 13

Iodine- thiosulfate titration equation

Answer 13

Question 14

Colour change in iodine thiosulfate

Answer 14

Iodine reacts, brown colour turns paler as it is converted to colourless iodide ions.​
​
Starch added near the end point. Solution turns blue/black to colourless when all iodine has been reduced.​