9. Inorganic chemistry - 9.4 Group VII

The similarities and trends in the physical and chemical properties of chlorine, bromine and iodine.

Content

I Characteristic physical properties

II The relative reactivity of the elements as oxidising agents

III Some reactions of the halide ions

IV The manufacture of chlorine

V The reactions of chlorine with aqueous sodium hydroxide

VI The important uses of the halogens and of halogen compounds (see also Section 10.3)

Learning outcomes

Candidates should be able to:

(a) describe the trends in volatility and colour of chlorine, bromine and iodine

(b) interpret the volatility of the elements in terms of van der Waals’ forces

(c) describe and deduce from E values the relative reactivity of the elements as oxidising agents

(d) describe and explain the reactions of the elements with hydrogen

(e) Stability

(f) describe and explain the reactions of halide ions with:

(g) outline a method for the manufacture of chlorine from brine by a diaphragm cell (see also Section 6)

(h) describe and interpret in terms of changes of oxidation number the reaction of chlorine with cold, and with hot, aqueous sodium hydroxide

(i) explain the use of chlorine in water purification

(j) recognise the industrial importance and environmental significance of the halogens and their compounds (e.g. for bleaches, PVC and halogenated hydrocarbons as solvents, refrigerants and in aerosols) (see also Section 10.3)