Do you have a redox equation you don't know how to balance? Besides simply balancing the equation in question, these programs will also give you a detailed overview of the entire balancing process with your chosen method.

1. Ion-electron method (also called the half-reaction method)
2. Oxidation number change method
3. Aggregate redox species method (or ARS method) - New on periodni.com [1]

BALANCING REDOX REACTIONS

The aggregate redox species method, or the ARS method in short, is an improved oxidation number change method that successfully solves even reactions that cannot be 'cleanly' separated into partial reactions of oxidation and reduction.

Enter an equation of a chemical reaction and click 'Submit' (for example:
h2so3 + kmno4 --> h2so4 + k2so4 + mnso4 + h2o ).

Rules for typing equations

• Spaces are irrelevant, for example Cu SO 4 is equal CuSO4
• All types of parentheses are correct, for example K3[Fe(CN)6]
• When writing ions simply put the charge at the end of the formula, for example Hg2+, Hg22+, or use the ^ character if you wish to be explicit, Hg2^2+
• To enter the equation sign, you can use either "=" or "-->" or "→" symbols.
• The equation can be written in lowercase letters. If the elements in a chemical formula are properly capitalized, the smart case converter leaves them as you have typed.

A balanced chemical equation accurately describes the quantities of reactants and products in chemical reactions. According to Filipović and Lipanović there are four basic rules for assembling the equation of a chemical reaction:[2]

1. Reactants and products of the chemical reaction must be known.
2. The number of atoms on the left side must be equal to the number of atoms on the right side of the equation.
3. The sum of the charges on one side of the equation must be equal to the sum of the charges on the other side.
4. The overall change in the oxidation number of oxidized atoms must be equal to the overall change in the oxidation number of reduced atoms.

Guidelines for balancing redox equations

• Step 1. Write an unbalanced equation
• Step 2. Identify the redox couples in the reaction
  • a) Assign oxidation numbers to each atom
  • b) Identify and write out all redox couples in a reaction
  • c) Remove all unnecessary redox couples
• Step 3. Aggregate redox species
  • a) Balance redox atoms that are not a part of a redox couple
  • b) Balance non-redox atoms that are present only in redox species
  • c) Combine the remaining equations into two partial equations
  • d) Equalize the number of electrons transferred in the partial equations
  • e) Add or combine the partial reactions together
• Step 4. Balance the rest of the atoms and charges
  • a) Add non-redox species and balance all other atoms except hydrogen and oxygen
  • b) Balance the charges with H+ or OH- (depending on medium)
  • c) Balance the oxygen atoms by adding H₂O
• Step 5: Simplify the equation
• Step 6. Check that the elements and charges are balanced

Sample redox equations

Sample non-redox equations

Bibliography:

1. E. Generalić, N. Vladislavić, Aggregate Redox Species Method - An Improved Oxidation Number Change Method for Balancing Redox Equations, Chemistry Journal, Vol. 4, No. 3, 43-49 (2018)
2. I. Filipović, S. Lipanović: Opća i anorganska kemija, Školska knjiga, Zagreb, 1995. (p.436)