Answer: 3Fe(OH)2 + MnO4- + 2H2O MnO2 + 3Fe(OH)3 + OH-
(b) Bi(OH)3 + SnO22- SnO32- + Bi
Answer: 2Bi(OH)3 + 3SnO22- 2Bi + 3H2O + 3SnO32-