March 05, 2013 Oxidizing and Reducing Agents Oxidizing Agents Reducing Agents -are reduced (gain e-) -are oxidized (lose e-) Examples Examples metals + metal ions (M ) anions (N-) non metals acids Not all OA's have the same Not all RA's have the same strength. Some are better strength. Some are better at gaining electrons. This at losing electrons. This makes them more reactive. makes them more reactive. (stronger) (stronger) March 05, 2013 Reducing Agents -are oxidized (lose e-) Examples Oxidizing Agents metals anions (N-) - Not all RA's have the same -are reduced (gain e ) strength. Some are better at losing electrons. This makes them more reactive. (stronger) Examples metal ions (M+) non metals acids Not all OA's have the same strength. Some are better at gaining electrons. This makes them more reactive. (stronger) When an OA is reduced, it becomes an RA 2+ - Cu (aq) + 2e ----> Cu(s) OA + e- ----> RA March 05, 2013 Example 2- + - SO4 (aq) + 4 H (aq) + 2e ---> H2SO3(aq) Is H2SO3(aq) an oxidizing agent or a reducing agent? When a RA is oxidized it becomes an OA 2+ - Pb(s) ---> Pb (aq) + 2e RA ---> OA + e- March 05, 2013 Rule for Comparing OA and RA strength If a substance is a strong OA, it is a weak RA in its reduced form. (and vice versa) OA + e- ---> RA Example Reactive metals like sodium are strong reducing agents. + Are Na (aq) a weak or strong oxidizing agent? March 05, 2013 Redox Tables A redox table is a series of reduction reactions listed with the strongest OA at the top left The strongest RA is on the bottom right The reactions are reversible (can be read forward and backwards March 05, 2013 Your redox table is on page 7 of the data book March 05, 2013 Which is a stronger OA 3+ Br2(l) or Fe (aq) 2- + + SO4 (aq) and H (aq) or Ag (aq) March 05, 2013 Fe2+ can gain electrons or lose electrons (this is common in multivalent metals) Write the half reaction when Fe2+ is reduced. Water can act as an OA or an RA. Write the reaction when water acts as an RA. Is water a weak or strong RA? March 05, 2013 A redox table can be used to determine if an OA and RA will react spontaneously with each other. Rule for Predicting Sponteneity An OA and RA will react spontaneously with each other if the OA is above the RA on the redox table Identify three metals that react spontaneously with nitric acid. March 05, 2013 + - A salt solution contains Na (aq) and Cl (aq). Do these ions react spontaneously with each other? Will H2(g) react spontaneously with copper (II) ions Will H2(g) react spontaneously with lead(II) ions March 05, 2013 bottom half March 05, 2013 March 05, 2013 http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::100%::100%::/sites/dl/free/ 0072512644/117354/06_Oxidation_Reduxn_Rxns.swf::Oxidation%20Reduction%20Reactions.