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Chapter 20

Group 7: The Halogens

20.1 Fluorine Irregularity & Physical State

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20.2 Comparative Halogen Reactions & Stabilities

• F2 > Cl2 > Br2 > I2 (oxidizing power) � forming F1-

> Cl1-

> Br1-

> I1-

respectively

• Remember that the oxidizer is always reduced (0�-1 oxidation number in this case)

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HX Stability

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Reaction with conc. H2SO4

• Note the extent of sulphur reduction by H+ in the case of iodine

• Conc. HCl will have the same oxidizing effect

• Conc H3PO4 is not an oxidizing acid and will only have the acid/base reaction effect

Reaction with AgNO3

Reaction with water (No dissolution)

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Reaction with water or alkali (Redox disproportionation)

Thermo-sensitive chlorate

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