available in the texts, has been presented in detail. Oxidation, reduction, oxidising agent ( oxidant ) and reducing agent ( reductant ) have been viewed according to each conceptualisation. Oxidation numbers are assigned in accordance with a consistent set of rules. Oxidation number and ion-electron method both are useful means in writing equations for the redox reactions.
Redox reactions are classified into four categories: combination, decomposition displacement and disproportionation reactions. The concept of redox couple and electrode processes is introduced here. The redox reactions find wide applications in the study of electrode processes and cells. EXERCISES .
Assign oxidation number to the underlined elements in each of the following species: (a) NaH PO (b) NaHSO (c) H P O (d) K MnO (e) CaO (f) NaBH (g) H S O (h) KAl(SO ) . H O . What are the oxidation number of the underlined elements in each of the following and how do you rationalise your results ? (a) KI (b) H S O (c) Fe O (d) CH CH OH (e) CH COOH .
Justify that the following reactions are redox reactions: (a) CuO(s) + H (g) → Cu(s) + H O(g) (b) Fe O (s) + 3CO(g) → 2Fe(s) + 3CO (g) (c) 4BCl (g) + 3LiAlH (s) → 2B H (g) + 3LiCl(s) + AlCl (s) (d) 2K(s) + F (g) → 2K + F – (s) (e) NH (g) + O (g) → 4NO(g) + 6H O(g) . Fluorine reacts with ice and results in the change: H O(s) + F (g) → HF(g) + HOF(g) Justify that this reaction is a redox reaction. . Calculate the oxidation number of sulphur, chromium and nitrogen in H SO , Cr O – and NO – .
Suggest structure of these compounds. Count for the fallacy. . Write