Group 2 And 7

Question 1

Oxidising agent

Answer 1

Electron acceptor as it’s reduced

Question 2

Br reduce H2SO4

Answer 2

2 equations
H2SO4 = SO2
Br-= BR2
Then combine

Question 3

How to balance half equations

Answer 3

Balance main atom.
Balance H with H+
Balbxe Obwith H2O
Balance charge with e-

Question 4

I reduce H2SO2

Answer 4

I = I2
H2SO4= S/SO2/H2S
And combine when balanced

Question 5

NaCl and NaF with H2SO4

Answer 5

NaCl + H2SO4 = HCl + NaHSO4
Misty fumes as they are too weak

Question 6

Halide test

Answer 6

Add AGNO3
Ag+ + Cl- = AgCl ( white ppt)
Ag+ + Br- = AgBr = cream ppt
Ag+ + I- = AgI ( yellow pot )
Then add dilute ammonia which dissolves white ppt but others remain
Add concentrated ammonia cream ppt dissolves but yellow ppt remains
Dissolving formula = AgCl + NH3 = Cl- + Ag(NH3)2+

Question 7

Halogen displacement reactions

Answer 7

Ionic equations
Cl2 + 2NaBr = Br2 + 2NaCl
Cl2 + 2Br- = Br2 + 2 Cl-

Question 8

Observations

Answer 8

I2 = black solid
Br2= brown / orange fumes
NaBr = orange solution
S = yellow solid
H2S =0 bad egg smell
SO2 = acidic gas

Question 9

Uses of chlorine

Answer 9

Sterilise water by killing bacteria and microorganisms what is added in low concentration as it is toxic
Equation = Cl2 + H2O = ( reversible ) HCl + HClO
Disproportion reaction

Question 10

Group 2 with water ( Mg )

Answer 10

Reactivity decreases
Mg + 2H2O (l) = Mg(OH)2 + H2
Mg + H2O (g) = MgO + H2 ( white solid and bright light )

Question 11

Group 2 hydroxides

Answer 11

Solubility increases
Mg(OH)2 = white ppt forms
Test for Mg 2+ = NaOH
Test for OH = MgCl2
Treat indigestion

Question 12

Group 2 sulphates

Answer 12

Solubility decreases down the group
BaSO4 = white ppt forms
Test for Ba2+ = H2SO4
Test for SO4 = BaCl2
For stomach x rays ( not toxic cause it’s insoluble in water )

Question 13

MG in extra extraction of TI from TICL4

Answer 13

TiCl4 + mg = mgCl2 + Ti