Question

Balance the following oxidation-reduction reactions, and show ALL steps:

1. MnO4- + Cl- <--> Mn2+ + Cl2

2. As2S3 + NO3- <--> HAsO3 + S + NO

Balance the ffollowing redox reactions and show ALL steps:

1. Fe3S4 + O2(g) <--> Fe(OH)3(s) + SO42-

2. FeS2(s) + NP3- <--> N2(g) + FeOOH(s) + SO42-

Answer 1

These steps need to be followed if in neutral conditions.

Step 1:Separate the half-reactions.

Step 2: Balance the electrons in the equations.

Step 3: Adding the equations and then cancel out the electrons to get a balanced equation.

These steps need to be followed if in acidic conditions:

Step 1: Separate the reaction into half-reactions.

Step 2: Balance all the elements in the half-reactions that are not hydrogen and oxygen.

Step 3: Add H2O molecules to balance any oxygen atoms.

Step 4: Next, balance the hydrogen atoms by adding protons (H+). Now, balance the charge by adding electrons and scale the electrons (multiply by the lowest common multiple) so that they will cancel out when added together.

Step 5: Finally, add the two half-reactions and cancel out common terms.

These steps need to be followed if in basic conditions:

Step 1: . Follow the same steps as for acidic conditions. The only difference is adding hydroxide ions (OH-) to each side of the net reaction to balance any H+.

Step 2: OH- and H+ ions on the same side of a reaction should be added together to form water.

Step 3: Again, any common terms can be canceled out.