Chemistry Forum

balance

1. Build Redox pair CrCl₃ /Na₂CrO₄ and H₂O₂/ OH-
2. Ions Cr₃+/ CrO₄ 2- and H₂O₂/ OH-
3. Alkaline condition OH-
4. Cr₃+ + 8 OH- => CrO₄ 2- + 4 H₂O
5. Balance Electron
Cr₃+ + 8 OH- => CrO₄ 2- + 4 H₂O + 3 e-

H₂O₂ + 2 e-=> 2 OH-
Kgv = 6 for Elektrons

2 Cr₃+ 16 OH-=> 2 CrO₄ 2- + 8 H₂O + 6 e-

3 H₂O₂ + 6 e- => 6 OH-

Addition

2 Cr₃+ 10 OH- + 3 H₂O₂ => 2 CrO₄ 2- + 8 H₂O
Adding Na+ + Cl-

2 CrCl₃+ 10 NaOH+ 3 H₂O₂ => 2 Na₂CrO₄ + 8 H₂O + 6 NaCl
Finished

I didn't understand what is being done

What do you don't understand? You have to pick the oxidation and Reduction Compounds on both side of the equation.
According it is alkaline ( NaOH) you add OH- on edukt side and get water on product side
Balance and add electrons for the balanced charge,
Then for both equation you get the electrons equal .
Then Addition of both equation, electrons and some water will be eliminated.
At the end you add the spectator ions sodium and chloride.

¿Como de balancea esta ecuación FeCl₃ + CaSO₃ = CaCl₂ + FeSO₂?

2 FeCl₃ + H₂O + CaSO₃ => 2 FeCl₂ + CaSO₄ + 2 HCl