K2Cr2O7 + KNO2 + H2SO4 => Cr2(SO4)3 + KNO3 + H2O + K2SO4
Can someone help me balance this chemical equation?
K2Cr2O7 + KNO2 + H2SO4
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Re: K2Cr2O7 + KNO2 + H2SO4
First start to find the redox pair
Cr2O7 2- and Cr 3+
NO2- and NO3-
Condition is acidic or alcaline?
If acidic reduction requires H+ and release water. And oxidation is vise versa
If alcaline reduction requires water and release OH- , Oxidation vise versa.
Cr2O7 2- + 14 H+ => 7H2O + 2 Cr 3+
Balance charge
Cr2O7 2- + 14 H+ + 6 e- => 7 H2O + 2 Cr 3+
NO2- + H2O => NO3- + 2 H+
Balance charge
NO2- + H2O => NO3- + 2 H+ + 2 e-
LCD of electron is 6
Second equation multiply by 3
3 NO2- + 3 H2O => 3 NO3- + 6 H+ + 6 e-
Addition
Cr2O7 2- + 8 H+ + 3 NO2- => 4 H2O + 2 Cr3+ 3 NO3-
Finished
Add spectator ions
K2Cr2O7 + 4 H2SO4 + 3 KNO2 => 4 H2O + Cr2(SO4)3 + 3 KNO3 + K2SO4
Cr2O7 2- and Cr 3+
NO2- and NO3-
Condition is acidic or alcaline?
If acidic reduction requires H+ and release water. And oxidation is vise versa
If alcaline reduction requires water and release OH- , Oxidation vise versa.
Cr2O7 2- + 14 H+ => 7H2O + 2 Cr 3+
Balance charge
Cr2O7 2- + 14 H+ + 6 e- => 7 H2O + 2 Cr 3+
NO2- + H2O => NO3- + 2 H+
Balance charge
NO2- + H2O => NO3- + 2 H+ + 2 e-
LCD of electron is 6
Second equation multiply by 3
3 NO2- + 3 H2O => 3 NO3- + 6 H+ + 6 e-
Addition
Cr2O7 2- + 8 H+ + 3 NO2- => 4 H2O + 2 Cr3+ 3 NO3-
Finished
Add spectator ions
K2Cr2O7 + 4 H2SO4 + 3 KNO2 => 4 H2O + Cr2(SO4)3 + 3 KNO3 + K2SO4