Basic solutions balancing oxidation-reduction reactions

Balancing oxidation-reduction reactions depends on whether the solution is acidic or basic. The method for balancing redox reactions in an acidic solution is as follows ... 

Balancing Oxidation-Reduction Reactions in Acidic and Basic Solutions... 

Oxidation—reduction reactions involve a transfer of electrons from one species to another. The half-reaction method can be applied to balancing oxidation-reduction reactions in acidic and basic solutions. Many of the principles required for balancing these reactions were presented in Chapter 4. 

Balancing oxidation-reduction equations for reactions occurring in aqueous acidic solutions is usually fairly straightforward since we can use H20 to balance O, and then H+ to balance H. In basic solution,... 

Balance the following oxidation-reduction reaction that occurs in basic solution ... 

Most aqueous reaction equations can be balanced by trial and error. Oxidation-reduction reactions require a more systematic approach to balancing equations using either an acidic or basic solution. 

The general procedure is to balance the equations for the half-reactions separately and then to add them to obtain the overall balanced equation. The half-reaction method for balancing oxidation-reduction equations differs slightly depending on whether the reaction takes place in acidic or basic solution. 

Oxidation-reduction reactions can occur in basic as well as in acidic solutions. The half-reaction method for balancing equations is slightly different in such cases. 

Balancing Oxidation-Reduction Equations Occurring in Basic Solution by the Half-Reaction Method... 

It turns out that most oxidation-reduction reactions occur in solutions that are distinctly basic or distinctly acidic. We will cover only the acidic case in this text, because it is the most common. The detailed procedure for balancing the equations for oxidation-reduction reactions that occur in acidic solution is given below, and Example 18.5 illustrates the use of these steps. 

The Half-Reaction Method for Balancing Equations for Oxidation-Reduction Reactions Occurring in Basic Solution... 

In Chapter 4 (Section 4.6) we introduced the half-reaction method of balancing simple oxidation-reduction reactions. We now extend this method to reactions that occur in acidic or basic solution. The steps used to balance these equations successfully are built upon those presented in Chapter 4. Keep in mind that oxidation-reduction reactions involve a transfer of electrons from one species to another. For example, in the reaction described in the chapter opener, zinc metal becomes zincfll) ion each zinc atom loses two electrons, and copper(II) ion becomes copper metal (each copper ion gains two electrons). 

To tackle more complex oxidation-reduction reactions in acidic and basic solutions, we need to review and discuss the essential information required to describe an oxidation-reduction reaction, which is called a skeleton equation. To set up the skeleton equation and then balance it, you need answers to the following questions ... 

Although the preceding skeleton equation is not complete, it does give the essential information about the oxidation-reduction reaction. Moreover, given the skeleton equation, you can complete and balance the equation using the half-reaction method. Let us see how to do that. We first look at balancing oxidation-reduction equations in acidic solution. To balance such equations in basic solution requires additional steps. 

Balancing equations in acidic and basic solutions by the half-reaction method Given the skeleton equation for an oxidation-reduction equation, complete and balance it. (EXAMPLES 20.1,20.2)... 

An oxidation-reduction reaction can also take place in basic solution. In that case, we use the same half-reaction method, but once we have the balanced equation, we will neutralize the with OH to form water. The is neutralized by adding OH to both sides of the equation to form H2O as shown in Sample Problem 15.5. 

Balance each of the following skeletal equations by using oxidation and reduction half-reactions. All the reactions take place in basic solution. Identify the oxidizing agent and reducing agent in each reaction. 

C21-0070. In basic aqueous solution, A1 acts as a strong reducing agent, being oxidized to AIO2. Balance this half-reaction, and determine balanced net reactions for A1 reduction of the following (a) NO3 to NH3 (b) H2 O to H2 and (c) Sn03 to Sn. 

An electrochemical cell should not be confused with a biological cell, which is the basic unit of life. Electrochemical cells contain chemical solutions and electrodes to conduct electrons. As shown in the figure on page 136, both oxidation and reduction reactions occur in the cell, but these reactions are separated. Separation is essential so that electrons can flow through electrodes and into attached wires, which can be routed to wherever electricity is needed. To maintain electrical balance at the electrodes—in other words, to complete the circuit so that electricity flows in a loop—an electrolyte allows the flow of ions between the two halves of the system. This cell produces electricity and is called a voltaic cell. The reaction proceeds as long as the materials last. 

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