Question

1)
Co-Co(NO3)2-CoOHNO3-Co(OH)2-K2[Co(OH)4]

2) No-NiSO4-Ni(OH)2-Ni(OH)3-NiCl2​

Answer 1

1) co + hno3 = Co(NO3)2 + 2 NO2 + 2 H2O
Co (no3)2 + naoh = coohno3 ( nano3
Coohno3 + naoh = co(oh)2 + nano3
Co(oh)2 + 2koh= K2[co(oh)4]
2)
Ni + h2so4 = niso4 + H2
Niso4 + 2naoh = Ni(oh)2 + na2so4
2Ni(oh)2 + h2o2 = 2Ni(oh)3
2Ni(oh)3 + 6hcl = 2nicl2 + 6h2o + cl2
Никель не образует тригалогенидов, поэтому так