Half-reaction equations, writing

As shown above, you can use half-reactions to write balanced net ionic equations for redox reactions. In doing so, you use the fact that no electrons are created or destroyed in a redox reaction. Electrons are transferred from one reactant (the reducing agent) to another (the oxidizing agent). 

Write a balanced half-reaction equation for the oxidation of Mo3+ t0 MoO in acid solution... 

Write balanced ionic half-reaction equations for the oxidation of each of the following reducing agents in acid solution. 

Balance the following redox reactions, using the half-reaction method. Write your answers as net ionic equations. 

For each of the following redox reactions, (i) write the half-reactions (ii) write a balanced equation for the whole reaction, (iii) determine in which direction the reaction will proceed spontaneously under standard-state conditions ... 

Given the before and after formulas of species containing elements that are oxidized and reduced in an acidic solution, write the oxidation and reduction half-reaction equations and the net ionic equation for the reaction. 

The steps for writing a half-reaction equation in an acidic solution are listed below. Each step is illustrated for the NOj -to-NO change in Example 19.11. 

After identifying the element oxidized or reduced, write a partial half-reaction equation with the element in its original form (element, monatomic ion, or part of a polyatomic ion or compound) on the left and in its final form on the right ... 

Now that you have the two half-reaction equations, finish writing the net ionic equation as you did before. 

In this section, each equation identifies an oxidizer and a reducer, as well as the oxidized and reduced products of the redox reaction. Write separate oxidation and reduction half-reaction equations, assuming that the reaction takes place in an acidic solution, and add them to produce a balanced redox equation. 

Write two half-reactions for the equation. We separate the equation into two half-reactions by writing one half-reaction for Fe and one for Mn. 

Using the ion-electron half-reaction method, write balanced equations for the following oxidation reactions. 

Identify the oxidising agent and the reducing agent in each reaction and write half-equations showing the donation or acceptance of electrons by each of these eight reagents. 

Ladder diagrams can also be used to evaluate equilibrium reactions in redox systems. Figure 6.9 shows a typical ladder diagram for two half-reactions in which the scale is the electrochemical potential, E. Areas of predominance are defined by the Nernst equation. Using the Fe +/Fe + half-reaction as an example, we write... 

We begin by writing unbalanced equations for the oxidation and reduction half-reactions in part (a). 

When potassium chlorate solution, KClOi, is added to hydrochloric acid, chlorine gas is evolved. Although we can find the half-reaction, 2C1- = Ck(g) + 2e, in Appendix 3, we find no equation with CIQT ion involved. We can surmise that CIO3" is accepting electrons and changing into chlorine. Let us write a partial half-reaction in which we indicate an unknown number of electrons and in which we have conserved only chlorine atoms ... 

Now we can return to working out the equation for the reaction we observed. The least common multiple between 1 and 5 is 5. Writing the half-reactions to involve 5 electrons and adding them, we obtain... 

One method of obtaining copper metal is to let a solution containing Cu+2 ions trickle over scrap iron. Write the equations for the two half-reactions involved. Assume the iron becomes Fe. Indicate in which half-reaction oxidation is taking place. 

We consider oxidation first. To show the removal of electrons from a species that is being oxidized in a redox reaction, we write the chemical equation for an oxidation half-reaction. A half-reaction is the oxidation or reduction part of the reaction considered alone. For example, one battery that Volta built used silver and zinc plates to carry out the reaction... 

Step 6 Write the overall equation. In the half-reactions, 2 electrons are lost, but 5 are gained, so we need 10 in each half-reaction. 

Sei f-Test 12.2B When iodide ions react with iodate ions in basic aqueous solution, triiodide ions, I,, are formed. Write the net ionic equation for the reaction. (Note that the same product is obtained in each half-reaction.)... 

Step 1 Write the equation for the electrode on the right of the cell diagram as a reduction half-reaction (remember Right for Reduction). 

---