Page 126 - Chemistry ICSE Class X

112 ICSE Chemistry – 10

— Reaction of metals with NaOH/KOH
Zn(s) + 2NaOH(aq) o Na ZnO (aq) + H (g)
2 2 2
(hot, conc.)
Pb(s) + 2NaOH(aq) o Na PbO (aq) + H (g)
2
2
2
(hot, conc.)
Al(s) + 2NaOH(aq) + 2H O o 2NaAlO (aq) + 3H (g)
2 2 2
(boiling, dilute)
— Reactions of acids and alkalis on metal oxides
Na O(s) + 2HCl(aq) o 2NaCl(aq) + H O(l)
2 2
(basic oxide)
CuO(s) + H SO o CuSO (aq) + H O(l)
2
4
4
2
(basic oxide)
— Amphoteric oxides. Metal oxides and metal hydroxides which show both acidic as well as basic character, that is, which
react with both acids and bases are called amphoteric oxides/hydroxides. For example, Al O and ZnO are amphoteric
2 3
oxides.
Al O (s) + 6HCl(aq) o 2AlCl (aq) + 3H O(l)
3
2
2 3
(basic)
Al O (s) + 2NaOH(aq) o 2NaAlO (aq) + H O(l)
2
2 3
2
(acidic)