Redox

Question 1

definition of redox

Answer 1

A chemical reaction involving both oxidation and reduction simultaneously

Question 2

What is an oxidising agent

Answer 2

A substance that oxidises other substances, itself being reduced in the process

Question 3

Common oxidising agent

Answer 3

Potassium manganate(VII) KMnO4, Potassium dichromate(VI) K2Cr2O7, Hydrogen peroxide H2O2, O2, Cl2

Question 4

Common reducing agent

Answer 4

Potassium iodide KI, Reactive metals(eg Zn, Al), H2, C, CO

Question 5

Reducing agent:
Potassium Iodide KI

Answer 5

Colourless solution turns brown

2I- = I2+2e-

can be identified using startch (turn blue-black)

Question 6

Oxidising agent:
Acidified potassium manganate (VII), KMnO4

Answer 6

Purple solution turns colourless

MnO4-+8H+ +5e- = Mn2+ + 4H2O

Question 7

Oxidising agent:
potassium dichromate(VI), K2Cr2O7

Answer 7

Orange solution will turn green

Cr2O72- + 14 H+ + 6e- = 2Cr3+ + 7H2O

Question 8

Definition of disproportionatiton

Answer 8

A redox reaction in which a single substance is simultaneously oxidised and reduced to form two different products

Question 9

Which species does not undergo a disproportionation reaction
ClO2-
ClO-
ClO4-

Answer 9

ClO4-

It is at maximum oxidation state, +7, it cannot be oxidised further