Physical Properties
Iodine Thiosulfate Titrations
WHY:
F
Cl
Br
I
F
Cl
Br
I
Size, Melting/ Boiling Point
INCREASES
Increase size increase V.d.W
therefore more heat energy
required to overcome
WHY:
Solubility, Electronegativity
DECREASES
(I soluble in KIaq)
Polarity decreases down group
2MX(S)
Disproportionation Reactions
X2 +2OH
X +XO- + H2O
Definition:
MXO
MX + MXO3
A species is oxidised and reduced at
Metal halate(I)
Metal Halide
the same time
Metal Halate (V)
F
Cl
Br
I
Displacement Reactions
X2 will displace X- if they
are more reactive.
Hydrogen Halides with NH3
NH3(g)+HX
NH4X(s)
Oxidation Reactions with Non Metals (Hydrogen)
F
Cl
Br
I
As
Reactivity with Hydrogen
DECREASES
Reaction with Phosphorous
and Cl2 makes
Phosphorous(III)Chloride
Excess Cl2 makes
Phosphorous(V)Chloride
Example
H2(g)+ X2 (g)
2P(S)+ 3Cl2 (g)
2PCl3(l)
2P(S)+ 5Cl2 (g)
2PCl5(l)
Testing for Silver Halides
Use HNO3 to remove impurities
Cl
White sol in NH3 (aq) Dilute
Br
Cream Sol in NH3(aq) Conc
I
Yellow insol in NH3(aq) Conc
MX +H2SO4
Cl
2HX(g)
2I-(aq) + S4O62-(aq)
-
Example
2M(s)+ X2 (g)
Overall Reaction
I2(aq) + 2S2O32-(aq)
2I-(aq)
Reducing Agent
2S2O32-(aq)
S4O62-(aq) + 2e-
Oxidation Reactions with Metals (M = Metal, X = Halogen)
Halogens react vigorously with
group 1 metals
Form ionic Bond
Oxidising Agent
I2(aq) + 2e-
OXIDISING AGENTS
Br
I
REDUCING AGENTS
All will produce Hydrogen Halide
NaCl + H2SO4
NaHSO4 + HCl
Br and I will react further
HBr + H2SO4
Br2 + H2O +SO2
H2SO4 8H+ 8I-
H2S 4H2O 4I2