1.4 Oxidation and Reduction Reactions

 

 

 

 

 

 

• Whenever one substance loses an electron (is oxidized), another substance must gain that electron (be reduced).

• The substance that gives up an electron and causes reduction is called a reducing agent.

• The substance that gains an electron and causes the oxidation is called an oxidizing agent. 

         

• Tests for an oxidizing agent are accomplished by mixing it with a substance that is easily oxidized to give a visible color change when the reaction takes place. 

   

   

• Oxidation and reduction or redox reactions occur simultaneously in a given reaction 

      Example 1.14: Identify the reducing and oxidizing agents in the following
       balanced redox reactions:  

 2Fe + 3O₂ → Fe₂O₃

      Assign oxidation states of the reactants and products, then identify the species oxidized and reduced.

• Fe is oxidized from 0 to +3

• O is reduced from 0 to –2 

        Therefore, Fe is reducing agent and O₂ is oxidizing agent. 

• Mg is oxidized from 0 to +2, therefore Mg is reducing agent.

•  H is reduced from +1 to 0, therefore HCl is the oxidizing agent.

     

1. Where do the most easily reduced and oxidized elements found in the periodic table of the elements?

   

• Transition elements at the right of the periodic table such as silver and copper can easily be reduced (strong oxidizing agents) from their compounds. 

• Alkali metals like potassium can easily be oxidized (strong reducing agents)