Phosphorus can have several different oxidation numbers ranging i...

Question

Phosphorus can have several different oxidation numbers ranging in value from -3 to +5.
(b) Based on oxidation numbers, which phosphorus oxide compound from part (a) was formed by combustion with a limited supply of oxygen?

Accepted Answer

Hello. Everyone in this video we're comparing tetra arsenic. Hex oxide with tetra arsenic tech oxide. And seeing which one will form the arsenic oxide that has limited supply of oxygen. So right here, we're basically just dealing with oxidation states. So let's go ahead and start off our calculations with tetra arsenic hex oxide. So this right here which will just spread everything in blue. So the formula for this is going to be what we have tetra arsenic. So that's four of our arsenic and hex oxide. So the prefix of hex is six. So we have six oxygen's all right. So we're gonna go ahead and let X equal to the oxidation state. So, os of arsenic and then we can see that the over our charge of our molecule is neutral, so that's equal to zero. So, again, we have our a. 406 and because our oxygen, let's see. So we said X is going to be the oxidation state of arsenic. So we have X. Component here. And the oxygen here is always going to be negative too. Alright, so we have everything equal to zero because it's a neutral molecule, we have four of our unknown. So we'll have four X. And then we're adding that. Well, let's see here, we have six atoms of oxygen. Each oxygen will provide negative two oxidation state. So just doing basic arithmetic here. So six times negative two is negative, 12 will bring the negative 12 to the other side giving us a positive 12. We're going to four X. Another, solving for X here, We just divide both sides by four. Giving us a positive three equal into X. Therefore the oxidation state of arsenic Is equal to Plus three. Alright, now, for the second one, let's do this in purple for our Tetra arsenic. Takac side. So the formula for this is going to be a S 40 10. So again, let X equal to the oxidation state of arsenic. Again, the overall molecule here is neutral. So we have a S 4010. Each oxygen ball provide negative two oxidation state and are arsenic is equal to X. Because we do not know the oxidation state. Again, we have our overall charge on zero. We have four unknowns and then we have 10 of our -2. Alright, again, just simple arithmetic again, 10 times negative two is negative 20. We'll bring the negative 22. The opposite of the equation sign. Now we're solving for X. Well divide both sides by XR by four, giving us a positive five equal into X. So here the oxidation state of arsenic is then equal to positive five. So here arsenic in the teacher arsenic, kayaks oxide. So the one on the left here has a lower oxidation number, soil form with a limited supply of oxygen. So we're comparing the oxidation states of both. This one is lower. So this will be the one that for the limited supply of oxygen. So therefore our answer then is going to be tetra arsenic extra oxide and this right here is going to be my final answer for this problem. Thank you all so much for watching.

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