The Chemical Reactions of the Halogens

Question 1

How do halogens usually react in chemical reactions?

Answer 1

Halogens react by gaining electrons to form negative ions with a charge of -1

Question 2

What happens to halogens during a redox reaction?

Answer 2

They are reduced (gain electrons) while oxidising another species

Question 2

What type of reactions do halogens undergo when they gain electrons?

Answer 2

Halogens undergo redox reactions where they act as oxidising agents and are themselves reduced

Question 3

How does the oxidising ability of halogens change as you move up Group 7?

Answer 3

The oxidising ability increases going up the group

Question 4

Which halogen is the most powerful oxidising agent?

Answer 4

Fluorine

Question 5

Arrange the halogens in order of increasing oxidising power:
1. Iodine
2. Bromine
3. Fluorine
4. Chlorine

Answer 5

1. Fluorine
2. Chlorine
3. Bromine
4. Iodine

Question 6

What is a displacement reaction in halogen chemistry?

Answer 6

A displacement reaction occurs when a more reactive halogen displaces a less reactive halide ion from a metal halide solution

Question 7

Will a less reactive halogen displace a more reactive halide?

Answer 7

No, a less reactive halogen cannot displace a more reactive halide

Question 7

What are spectator ions in the reaction between chlorine and sodium bromide?

Answer 7

Sodium ions (Na+) are spectator ions because they do not change during the reaction

Question 8

What is the general rule: A halogen will displace the ion of a halogen ? it in the Periodic Table

Answer 8

Below

Question 9

Is the halogen (CHLORINE|Cl2) displacing the halide (BROMIDE|Br-)?

If yes: What is observed during the reaction?
Write the ionic equation

Answer 9

Chlorine displaces bromide
In this reaction, a yellow solution forms because bromine forms

Ionic equation: Cl2 + 2Br- ⇒ 2Cl- + Br2

Question 10

Is the halogen (CHLORINE|Cl2) displacing the halide (IODINE|I-)?

If yes: What is observed during the reaction?
Write the ionic equation

Answer 10

Chlorine displaces iodide
In this reaction, a brown solution forms because iodine forms

Ionic equation: Cl2 + 2I- ⇒ 2Cl + I2

Question 11

Is the halogen (BROMINE|Br2) displacing the halide (CHLORIDE|Cl-)?

If yes: What is observed during the reaction?

Answer 11

Bromine does not displace chloride
In this reactions the solution stays yellow because there is no reaction

Question 12

Is the halogen (BROMINE|Br2) displacing the halide (IODIDE|I-)?

If yes: What is observed during the reaction?
Write the ionic equation

Answer 12

Bromine does displace iodide
In this reactions a brown solution forms because iodine forms

Ionic equation: Br2 + 2I- ⇒ 2Cl + I2

Question 13

Is the halogen (IODINE|I2) displacing the halide (CHLORIDE|Cl-)?

If yes: What is observed during the reaction?

Answer 13

Iodine does not displace chloride
In this reaction the solution stays brown because there is no reaction

Question 14

Is the halogen (IODINE|I2) displacing the halide (BROMIDE|Br-)?

If yes: What is observed during the reaction?

Answer 14

Iodine does not displace bromine
In this reaction the solution stays brown because there is no reaction

Question 15

Why do halogens become weaker oxidising agents down Group 7?

Answer 15

This is because as you go down the group, atoms are larger and have more electron shielding, making it harder to gain an electron