1/ Na2SO4 + Pb(NO3)2 →.....................
2/ Na2S + Pb(NO3)2 →....................
3/ HCl + Fe2O3 →..................
4/ HCl + AgNO3 →..................
5/ HCl + Fe3O4 →...................
6/ HCl + MnO2 →..........................
7/ HCl + FeO →......................
8/ H2SO4 loãng + Fe →....................
9/ H2SO4 loãng + Na2SO3→..........................
10/ H2SO4 loãng + Na2S →..................