Question

hi, i understand how to solve this problem but how do we get 5 electrons in the reduction part. All the oxidation number make sense. I'm confused on where the 5 electrons came from.

o0 EXPLANATION As always, when you need to analyze a redox reaction, it's a good idea to start by identifying what's reduced and what's oxidized: +7-2 +1 2+ 2+ MnO (aq) 8H (aq) + 5 Fe (aq) Mn (aq) 4H,O)5 Fe(ag) Assigning oxidation states tells you Mn atoms are what's reduced and Fe atoms are what's oxidized. Knowing what's being reduced and oxidized will help you "take apart the redox reaction into its reduction and oxidation half-reactions. MnO (aq)+8 H (aq)+Se Fe (aq)+e Mn (aq)+4 H,O() 24 reduction: Fe (aa) oxidation: More... You can use the half-reactions to answer the first two questions in the table. You'll need to keep in mind two additional facts about galvanic cells: Reduction always takes place at the cathode

Answer 1

the given reaction as well as half reactions are balanced in both by the number of atoms and total charges over reactants and products.

in the process of balancing redox reactions we use H⁺ , OH^- and H₂O to balance the the number of oxygen and hydrogen atoms and in this process the total charges in get unbalanced.

Hence we add electrons on that side where positive charges are in excess and on the opposite side in case of excess negative charges.

the given half reaction is already balanced and electrons are added to balance the excess positive charge due to 8H⁺