(1)2KMnO 4
K 2MnO 4+MnO 2+O 2↑
(2)C 2H 5OH+3O 2
2CO 2+3H 2O
(3)CO 2+Ca(OH) 2
CaCO 3 ↓ +H 2O
(4)CaCO 3+2HCl
CaCl 2+H 2O+CO 2↑