Group 2 And group 7

Question 1

What is a halide

Answer 1

Group 7 with an ion 1- charge
Eg I-

Question 2

What do hallides behave as?

Answer 2

Reducing agent

Question 3

What is a reducing agent?

Answer 3

Electron pair donor

Question 4

Reducing strength of hallides

Answer 4

Increase down the group
Ionic radius increases
Weaker attraction between outer electron and nucleus

Question 5

Two ions that can reduce sulphuric acid

Answer 5

Br = SO2
I= SO2 , H2S , S
Write out half equations for both and combine

Question 6

What is SO2?

Answer 6

Acidic gas

Question 7

What is H2S?

Answer 7

Bad egg smell

Question 8

What is S?

Answer 8

Sulphur, which is a yellow solid

Question 9

Half equation of I- to I

Answer 9

2I- = I2 + 2e-

Question 10

What does I2 appear as

Answer 10

Black solid

Question 11

What does BR2 appear as

Answer 11

Brown fumes

Question 12

Halide test

Answer 12

1. Dissolve sample in water.
2. AddHNO3 Acid to remove any possible carbonate impurities which would give a false positive and don’t add HCL or sulphuric acid for the step
3. Add AgNo3 Solution
   Ag+ + Cl- = AgCl = white ppt
   Ag+ + Br- = AgBr = cream ppt
   Ag+ + I-=AgI= yellow ppt
   Ag+ +f- =AgF = colourless solution
4. Add dilute nitric acid
   White precipitate dissolves cream and yellow precipitate insoluble
5. Add concentrated ammonia to the sample
   Cream precipitate dissolves but yellow precipitate insoluble

Question 13

Equation with NH3 in halide test

Answer 13

AgCl + 2NH3 → Ag(NH3)2+ + Cl−
AgBr + 2NH3 → Ag(NH3)2+ + Br−

Question 14

What are halogens?

Answer 14

Diatomic molecules
Eh F2

Question 15

What does a halogen behave as?

Answer 15

Oxidising agent

Question 16

What is a oxidising agent?

Answer 16

Electron acceptor

Question 17

Trend in oxidising ability of halogens

Answer 17

Decreases down the group as larger radius so weaker attraction between nucleus and incoming electron

Question 18

Order of displacement reactions

Answer 18

I2= most powerful
Cl = weakest

Question 19

Use of chlorine

Answer 19

Added to water to sterilise water by killing bacteria and microorganisms

Question 20

Why is chlorine added in low concentrations?

Answer 20

Because it is toxic

Question 21

Reaction between chlorine and water

Answer 21

Cl2 + H2O ⇌ HCl + HClO

Question 22

What type of reaction is between chlorine and water?

Answer 22

Disproportionation reaction as chlorine is reduced to HCl and chlorine is oxidised to HClLO

Question 23

Chlorine + Sodium Bromide → Bromine + Sodium Chloride

Answer 23

Cl2 + 2NaBr → Br2 + 2NaCl
Cl2 + 2Br− → 2Cl− + Br2

Question 24

Chlorine + Sodium Iodide → Iodine + Sodium Chloride

Answer 24

Cl2 + 2NaI → I2 + 2NaCl
Cl2 + 2I− → 2Cl− + I2

Question 25

Bromine + Sodium Iodide → Iodine + Sodium Bromide

Answer 25

Br2 + 2NaI → I2 + 2NaBr Br2 + 2I− → 2Br− + I2

Question 26

Reactivity of group 2 metals down the group

Answer 26

Decreases

Question 27

Reaction of group 2 metals with liquid water

Answer 27

Mg(s) + 2H2O(l) → Mg(OH)2(aq) + H2(g)

Question 28

Reaction of group 2 metals with steam

Answer 28

Mg(s) + H2O(g) → MgO(s) + H2(g)

Question 29

Observation of MgO

Answer 29

White solid produce Bright light

Question 30

Use of Mg in Extraction of Ti from TiCl4

Answer 30

TiCl4 + 2Mg 2MgCl2 + Ti

Question 31

Group 2 hydroxide. Solubility.

Answer 31

Increases down the group

Question 32

Magnesium hydroxide equation and. Observation.

Answer 32

Mg2+(aq) + OH−(aq) → Mg(OH)2(s) White ppt

Question 33

What could you use to test for the presence of Mg2+ ions in a solution?

Answer 33

NaOH

Question 34

What could you use to test for the presence of OH− ions in a solution?

Answer 34

Mg(NO3)2

Question 35

Uses of Magnesium Hydroxide:

Answer 35

• Indigestion relief • Often called ‘milk of magnesia’

Question 36

Group 2 sulphate solubility

Answer 36

Decreases down the group

Question 37

Ionic equation of barium sulphate. And observation.

Answer 37

Ba2+(aq) + SO42−(aq) → BaSO4(s) White ppt

Question 38

What could you use to test for the presence of Ba2+ ions in a solution?

Answer 38

H2SO4

Question 39

What could you use to test for the presence of SO42− ions in a solution

Answer 39

BaCl2

Question 40

Use of barium sulphate

Answer 40

Taking X-rays of the stomach (Barium meal)

Question 41

Sodium chloride and fluoride when reducing H2SO4

Answer 41

Both are too weak so form steamy / misty fumes NaCl + H2SO4 = HCl +NaHSO4