А)CuSO4+2NaOH--->Na2SO4+Cu(OH)2
Cu+SO4+2Na+2OH--->2Na+SO4+Cu(OH)2
Cu+2OH--->Cu(OH)2
б)2na3po4+3pb(no3)2--->6nano3+pb3(po4)2
6na+2po4+3pb+6no3---->6na+6no3+pb3(po4)2
2po4+3pb--->pb3(po4)2
в)na2s+2agno3--->ag2s+2nano3
2na+s+2ag+2no3-->ag2s+2na+2no3
s+2ag--->ag2s