Basic solution balancing oxidation-reduction equations

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,... 

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. 

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

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. 

Additional Steps for Balancing Oxidation-Reduction Equations in Basic Solution... 

Balance the oxidation-reduction equation for the oxidation of Zn(s) by NaN03(aq) to produce Na2Zn (OH)4 and NH3(aq) in basic aqueous solution. 

To balance an oxidation—reduction equation in basic solution, you begin by balancing the equation as if it were a reaction in acidic solution. Then, you add the following 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)... 

Balance the following oxidation—reduction equations. The reactions occur in basic solution. 

Oxidation-reduction equations are now balanced using half-reactions in acidic or basic solutions. 

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. 

Write partial equations for the oxidation and the reduction. Then (1) Balance charges by adding in acid solutions or OH in basic solutions. (2) Balance the number of O s by adding H O s to one side. (3) Balance the number of H s by adding H s to one side. The number added is the number of equivalents of oxidant or reductant. 

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. 

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. 

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. 

Complete and balance the following equations for oxidation-reduction reactions that occur in basic solution ... 

In the half-reaction method, we usually begin with a skeleton ionic equation showing only the substances undergoing oxidation and reduction. In such cases, we assign oxidation numbers only when we are unsure whether the reaction involves oxidation-reduction. We will find that (for acidic solutions), OH (for basic solutions), and H2O are often involved as reactants or products in redox reactions. Unless H, OH , or H2O is being oxidized or reduced, these species do not appear in the skeleton equation. Their presence, however, can be deduced as we balance the equation. 

A few redox reactions have more than one oxidation half-reaction or more than one reduction half-reaction. Balancing the equations for these reactions is more complicated. However, the multiple half-reactions are often stoichiometricaUy hnked. Maintain the correct ratio of the elements and balance the electron transfer by multiplying them both by the same integer. Balance the following net ionic equation for a reaction in basic solution. OH" or HjO (but not H" ") may be added as necessary. 

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 ... 

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. 

A Method for Balancing Equations for Oxidation-Reduction Reactions That Occur in an Acidic or a Basic Aqueous Solution... 

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