Помогите расставить коэффициенты : 1) NO2+H2O+O2 = HNO3 2) HCL + Na2S = H2S+ NaCl 3) Cr+Cl2 = CrCl3 4) Na2O +H2O = NaOH
4NO2+2H2O+O2=4HNO3
2HCL + Na2S = H2S+ 2NaCl
2Cr+3Cl2 = 2CrCl3
Na2O +H2O = 2NaOH