10.2 Chemical reactions of halogens

Question 1

What is oxidation ability for the halogens

What type of reaction are these

Answer 1

. How easily they can gain an electron to become 1- ions, so they reduce themselves but oxidise other elements

Redox reactions

Question 2

Pattern of oxidation ability down group 7 and explain

Answer 2

. Oxidation ability decreases going down the group

Because the number of filled energy levels increases down the group so attraction between the positive nucleus and negative outer electron shell decreases so it becomes more difficult for the atom to gain electrons to become a 1- ion

Eg fluorine has the best oxidising power

Question 3

What is the oxidation power of chlorine half equation

Answer 3

Cl2 + 2e- —> 2Cl-

Question 4

What is a displacement reaction with the halides

Answer 4

. Halogens react with metal halides in a solution so the halide in the compound is replaced by a more reactive halogen, but not by a less reactive one.

Question 5

What is the reaction for chlorine displacing bromide ions with the oxidation/reduction numbers on top

What is the ionic equation

What are the spectator ions?

Answer 5

0 1- 0 1-
Cl2(aq) + 2NaBr(aq) —> Br2(aq) + 2NaCl(aq)

Cl2 + 2Br- —> Br2 + 2Cl-

Sodium ions

Question 6

What is the pattern of halogens when displacing and oxidising

Answer 6

They always displace the ion of the halogens below it

Eg F2 displaces Cl-

Br2 displaces I-

Question 7

Which halogen has the strongest oxidising power

Answer 7

. Flourine

Question 8

How is bromine extracted from sea water

Answer 8

. Sea water has bromine ions which can be oxidised by chlorine to produce bromine

Cl2 + 2Br- —>Br2 +2Cl-

Question 9

What can you see in the reaction between chlorine and sodium bromide

Answer 9

The two colourless starting materials react to make the red/brown colour of bromine