Determine whether each reaction is a redox reaction. For each redox reaction, identify the oxidizing agent and the reducing agent. a. Al(s) + 3 Ag+ (aq)¡Al3 + (aq) + 3 Ag(s) b. SO3( g) + H2O(l )¡H2SO4(aq) c. Ba(s) + Cl2( g)¡BaCl2(s) d. Mg(s) + Br2(l )¡MgBr2(s)

Video transcript

Hey everyone today, we're being asked to identify the reducing and oxidizing agents in the reaction between antimony and nitric acid to form antimony oxide, nitric oxide and water. So, to find the reducing and oxidizing agents, we first need to identify which molecules are being oxidized and reduced in the reaction. And to do this, we first need to find the oxidation states of the molecules before they react in the react inside and after the reaction has proceeded on the react inside. So let's go ahead and take a look at the reactions. 1st We have two molecules of antimony And two molecules of nitric acid. Taking a look at antimony first, it is a free metal. It is a free element and this is how it exists in its most stable state in nature if it was isolated from external conditions like oxide or oxidation. But as we can recall from our oxidation rules, a free element will have an oxidation state of zero. So antimony will have an oxidation state of zero for metric acid. The molecule in question that we really need to worry about being oxidized or reduced is the nitrogen. And this is because we have rules for oxygen and hydrogen, but nitrogen can have different oxidation states depending on what molecules it is bonded to. Now, we're dealing with a neutral molecule here, which means all the oxidation states must add up to zero. Going with our oxidation state rules, we know that oxygen will not paired to hydrogen peroxide or a flooring will have an oxidation state of negative two. And since there are three oxygen's in nitric acid, this means there is a total oxidation state of negative six. For the oxygen's similarly hydrogen when bonded to a non metal such as nitrogen or carbon or oxygen or a alike will have an oxidation state of plus one. And since we only have one, that is that So therefore all the other molecules excluding nitrogen, have a total oxidation state of plus five or sorry, -5. This means to counteract that and make it neutral nitrogen must have an oxidation state of plus five. Nitrogen is equal to Plus five. Taking a look at the reactor or the products now In s. p two, 03 Plus two nitric oxides, plus water. So in sp two or 3 or Antoninus oxide, we now have three oxygen's and we can go ahead and use the same rules that we used earlier. Each oxygen has a negative two oxidation state and we have three of them. So that makes us -6. However, we have to Anthony's that are bonded to it. So we need a plus six charge to counteract the negative six coming from the +03. However, this needs to be split into two because we have to antimony. So the total charge of sp two would then be plus six, which means each single Antimony would then go from zero two plus three because two plus three and plus three added together give us plus six. So this goes from 0 to plus three. In nitrogen we now have negative two from the oxygen. And The nitrogen then becomes plus 2 to counteract this. So we go from plus 5 to plus two. So what this effectively means is that antimony after the reaction is preceded has lost three electrons. It lost three electrons. Which means that it has been oxidized. Because remember our acronym for oxidation and reduction is oil rig. Where oil stands for oxidation is losing and rig stands for reduction is gaining of electrons. Similarly, nitrogen goes from plus five to plus two which means let me just write that with blue plus two which means it is gaining three electrons. It is gaining the three electrons that have been lost from the oxygen. So this is being reduced. However, we're still not done here. If oxide if antimony is being oxidized and the nitrogen and by respect the nitric acid is being reduced, then this means that the oxidation agent is therefore the nitric acid. So HN 03 is our oxidizing agent because it is being reduced and therefore helping or aiding the oxidation of antimony. It is an oxidizing agent Since similarly antimony is our reducing agent because it is being oxidized, meaning it aids the reduction of nitric acid reducing agent. I hope this helps and I look forward to seeing you all in the next one