Balancing redox reactions occurring in acidic solutions

In summary, the conversation is about balancing redox reactions in an acidic solution, specifically the reaction of PbO2 and I-. The steps to balance the reaction include writing out the half reactions, balancing oxygens and hydrogens, adding electrons to balance the equations, and combining the half reactions. The key to balancing is first balancing the atoms and then using electrons to balance the charge in the half reaction.
  • #1
shikam08
2
0

Homework Statement


Balance the following redox reactions occurring in an acidic solution.


Homework Equations


PbO2(s)+I-(aq)---->Pb2+(aq)+I2(s)


The Attempt at a Solution


1.) half reactions:
a.) reduction: I-(aq)----->I2(s)
b.) oxidation: PbO2(s)------>Pb2+(aq)
2.) balance Oxygens and Hydrogens
PbO2+4H+------>Pb2++2H2O
3.) add electrons to balance equations
a.)PbO2+4H++4e---->Pb+2+2H2O
b.) 4I--->4I2+4e-
4.) cancel out the electrons and combine the half reactions
PbO2+4H++4I--->Pb2++4I2+2H2O
 
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  • #2
shikam08 said:
b.) 4I--->4I2+4e-

Nope.
 
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  • #3
I don't understand how to insert the number of electrons on both sides to balance the equations and cancel out the electrons.
 
  • #4
Balance atoms first, then use electrons to balance charge in half reaction. As long as charge on both sides is different, equation is not balanced.
 
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1. How do I determine the oxidation states of the elements in a redox reaction?

To determine the oxidation states, you can use the following rules:- The oxidation state of an uncombined element is always 0.- The oxidation state of a monatomic ion is equal to its charge.- The sum of the oxidation states of all atoms in a neutral compound is 0.- The sum of the oxidation states of all atoms in a polyatomic ion is equal to its charge.- Group 1 elements have an oxidation state of +1 and Group 2 elements have an oxidation state of +2.- Fluorine has an oxidation state of -1 in all its compounds.- Oxygen has an oxidation state of -2 in most compounds, except in peroxides where it has an oxidation state of -1.- Hydrogen has an oxidation state of +1 when bonded to nonmetals and -1 when bonded to metals.

2. What is the difference between oxidation and reduction?

Oxidation is the loss of electrons by a species, while reduction is the gain of electrons by a species. These two processes always occur together in a redox reaction.

3. How do I balance a redox reaction occurring in an acidic solution?

To balance a redox reaction in an acidic solution, follow these steps:1. Write the unbalanced equation.2. Determine the oxidation states of all elements in the reactants and products.3. Identify which elements are being oxidized and reduced.4. Add H2O molecules to balance the oxygen atoms.5. Add H+ ions to balance the hydrogen atoms.6. Add electrons to balance the charges on each side of the equation.7. Check that the number of atoms and charges are balanced on both sides of the equation.8. If necessary, multiply the half-reactions by a coefficient to ensure that the number of electrons are equal in both half-reactions.9. Add the two half-reactions together and simplify, if possible.

4. Can I balance a redox reaction in a basic solution using the same method as in an acidic solution?

No, you cannot balance a redox reaction in a basic solution using the same method as in an acidic solution. In a basic solution, you must add OH- ions to balance the H+ ions. Once the reaction is balanced, you can then convert the OH- ions to H2O molecules on both sides of the equation.

5. Are there any shortcuts or tricks for balancing redox reactions in acidic solutions?

Yes, there are a few shortcuts and tricks that can make balancing redox reactions in acidic solutions easier. For example, you can balance the oxygen atoms first, then balance the hydrogen atoms and finally add the electrons. You can also try balancing the elements that appear in only one half-reaction first. Additionally, you can use the "half-reaction" method where you break the reaction into two half-reactions, balance them separately, and then combine them to get the overall balanced equation.

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