Redox Reaction

Question 1

For Oxidation,
Hydrogen is ____
Oxygen is ____
Electrons are ____
____ in oxidation state

Answer 1

Lost
Gained
Lost
Increase

Question 2

For Reduction,
Hydrogen is ____
Oxygen is ____
Electrons are ____
____ in oxidation state

Answer 2

Gained
Lost
Gained
Decrease

Question 3

What is oxidation state?

Answer 3

It is the charge an element would have if it existed as an ion in a compound

Question 4

What does an oxidising agent do? Examples of oxidising agents.

Answer 4

-Oxidises another substance, while being reduced itself
-oxygen, chlorine, potassium manganate(VII)

Question 5

What does a reducing agent do? Examples of reducing agents.

Answer 5

-Reduces another substance, while being oxidised itself
-hydrogen, carbon, potassium iodide

Question 6

If Potassium Manganate (VII) is added to a reducing agent, what will be observed? Why?

Answer 6

Solution turns from purple to colourless. In a positive test, manganate(VII) ions are reduced to manganese(VII) ions by reducing agent

Question 7

If Potassium Iodide is added to an oxidising agent, what will be observed? Why?

Answer 7

Solution turns from colourless to yellow-brown.
In a positive test, iodide ions are oxidised to iodine ions by the oxidising agent.

Question 8

How to test for a gaseous reducing agent?

Answer 8

Use strip of filter paper with spot of acidified potassium manganate(VII).
if it decolourises when exposed to gas, gas is reducing agent

Question 9

How to test for a gaseous oxidising agent?

Answer 9

Use strip of filter paper with spot of potassium iodide solution.
if it turns yellow-brown when exposed to gas, gas is oxidising agent.

Question 10

What to do if when testing for gaseous oxidising agent, results are pale?

Answer 10

Add a few drops of starch, and solution will turn dark blue if iodine is present.