OXIDATION REDUCTION REACTIONS

Question 1

What is an oxidation-reduction reaction?

Answer 1

A chemical reaction where the oxidation state of one or more substances changes.

Question 2

True or False: In an oxidation reaction, a substance gains electrons.

Answer 2

False

Question 3

What is oxidizing agent?

Answer 3

A substance that gains electrons and is reduced in a chemical reaction.

Question 4

What is reducing agent?

Answer 4

A substance that loses electrons and is oxidized in a chemical reaction.

Question 5

Fill in the blank: In a redox reaction, the substance that is oxidized is the one that _______.

Answer 5

loses electrons

Question 6

What color change indicates the presence of an oxidizing agent when using potassium permanganate?

Answer 6

The solution changes from purple to colorless.

Question 7

What is the oxidation state of oxygen in most compounds?

Answer 7

−2

Question 8

What happens to the oxidation states of elements in a redox reaction?

Answer 8

They change; one element is oxidized and another is reduced.

Question 9

True or False: In redox reactions, both oxidation and reduction occur simultaneously.

Answer 9

True

Question 10

What test can be used to identify a reducing agent?

Answer 10

Adding a solution of iodine, which will turn blue-black.

Question 11

What is the general equation for a redox reaction?

Answer 11

Oxidation half-reaction + Reduction half-reaction.

Question 12

Fill in the blank: The gain of oxygen or loss of hydrogen indicates _______.

Answer 12

oxidation

Question 13

What is the oxidation state of hydrogen in most compounds?

Answer 13

+1

Question 14

What color indicates the presence of a reducing agent in the presence of dichromate?

Answer 14

The solution changes from orange to green.

Question 15

What is a common laboratory method to test for oxidizing agents?

Answer 15

Using a reducing agent that changes color.

Question 16

What is the oxidation state of chlorine in NaCl?

Answer 16

-1

Question 17

True or False: Oxidation can occur without reduction.

Answer 17

False

Question 18

What is the main characteristic of a spontaneous redox reaction?

Answer 18

It occurs without external intervention.

Question 19

Fill in the blank: The element that undergoes oxidation loses _______.

Answer 19

electrons

Question 20

What is the role of an electron carrier in biological systems?

Answer 20

To transport electrons during redox reactions.

Question 21

What does the term ‘oxidation state’ refer to?

Answer 21

The hypothetical charge of an atom in a compound.

Question 22

What happens to the oxidation state of an element that is reduced?

Answer 22

It decreases.

Question 23

What is a common example of a reducing agent?

Answer 23

Hydrogen gas (H2)

Question 24

What does the term ‘redox potential’ indicate?

Answer 24

The tendency of a chemical species to acquire electrons and be reduced.

Question 25

True or False: All oxidation-reduction reactions involve oxygen.

Answer 25

False

Question 26

What is the oxidation state of iron (Fe) in Fe2O3?

Answer 26

+3

Question 27

Fill in the blank: A substance that is oxidized _______ electrons.

Answer 27

loses

Question 28

What is the significance of the half-reaction method?

Answer 28

It allows for the separation of oxidation and reduction processes.

Question 29

What is the oxidation state of carbon in methane (CH4)?

Answer 29

-4

Question 30

What is the effect of increasing temperature on the rate of redox reactions?

Answer 30

It generally increases the reaction rate.

Question 31

What does a redox titration typically involve?

Answer 31

A reaction between an oxidizing agent and a reducing agent.

Question 32

True or False: In a redox reaction, the total number of electrons lost equals the total number of electrons gained.

Answer 32

True

Question 33

What is the main property of oxidizing agents?

Answer 33

They have a high electronegativity.

Question 34

Fill in the blank: The process of gaining electrons is called _______.

Answer 34

reduction

Question 35

What is a common test for reducing sugars?

Answer 35

Benedict's test

Question 36

What happens during the corrosion of metals?

Answer 36

Oxidation occurs, leading to the formation of metal oxides.

Question 37

What is the role of sulfuric acid in redox reactions?

Answer 37

It often acts as an electrolyte or medium for the reaction.

Question 38

True or False: Redox reactions are only important in organic chemistry.

Answer 38

False

Question 39

What is the oxidation state of nitrogen in ammonia (NH3)?

Answer 39

-3

Question 40

What type of reaction is photosynthesis in terms of redox?

Answer 40

A reduction reaction, where carbon dioxide is reduced to glucose.

Question 41

What is the effect of pH on redox reactions?

Answer 41

It can alter the availability of protons and thus influence the reaction.

Question 42

Fill in the blank: In electrochemistry, the electrode where reduction occurs is called the _______.

Answer 42

cathode

Question 43

What is the oxidation state of sulfur in H2SO4?

Answer 43

+6

Question 44

What is a common characteristic of all redox reactions?

Answer 44

They involve a transfer of electrons.

Question 45

True or False: Redox reactions can occur in both acidic and basic solutions.

Answer 45

True

Question 46

What is a common example of an oxidizing agent?

Answer 46

Potassium permanganate (KMnO4)

Question 47

Fill in the blank: The process of losing electrons is known as _______.

Answer 47

oxidation