2 2 4 2 5 2 2 1 - Валентность
CO , MnO2 , Cl2O5 , CaCL2
Cr₂O₇²⁻+14H⁺+6e=2Cr³⁺+7H₂O |1
NO₂⁻+H₂O-2e=NO₃⁻+2H⁺ | 3
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Cr₂O₇²⁻+14H⁺+3NO₂⁻+3H₂O=2Cr³⁺+7H₂O+3NO₃⁻+6H⁺
Cr₂O₇²⁻+8H⁺+3NO₂⁻+=2Cr³⁺+4H₂O+3NO₃⁻
K₂Cr₂O₇+4H₂SO₄+3NaNO₂=Cr₂(SO₄)₃+3NaNO₃+K₂SO₄+4H₂O
M(HCl)=14,6г
m(H2O)=385,4 г
mp-pa=m(HCl)+m(H2O)=14,6+385,4=400г
W%=m(HCl)/mp-pa *100%=14,6/400 *100%=3,65%