Please help with this redox passage?

[m25]

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I came across this passage about redox experiment and I honestly don't understand what is happening beyond the fact that metals are being oxidized and acids are being reduced. I uploaded the passage and answers that were given in the book.

My main concern is question #2. How do we know from the experiment that nitrate ion has a higher reduction potential than H+? I thought it was nitric acid(HNO3) that has a higher reduction potential than hydrochloric acid (HCl) and sulfuric acid (H2SO4) And how are we supposed to tell that sulfate ion is NOT a better oxidizing agent than H+?

And for question 3, are we just supposed to know that NO2 is is acrid, orange-brown gas?

Lastly, in the passage, what does it mean in the last paragraph when it says "pairs of metals with similar reduction potentials were in reversed order half of the time" What does reversed order mean??

Any help with this would be much appreciated.

 

[Teleologist]

My main concern is question #2. How do we know from the experiment that nitrate ion has a higher reduction potential than H+? I thought it was nitric acid(HNO3) that has a higher reduction potential than hydrochloric acid (HCl) and sulfuric acid (H2SO4) And how are we supposed to tell that sulfate ion is NOT a better oxidizing agent than H+?

First, it's not nitric acid that's doing anything. Nitric acid doesn't even exist in high concentration. It's the nitrate anion doing the cool stuff cause nitrate ion is what you have in the system mainly. You know from the data table; the nitric acid solution tends to oxidize metals vigorously or violently.

And for question 3, are we just supposed to know that NO2 is is acrid, orange-brown gas?

Why would have you have to know this? If nitrate anion is the oxidizing agent, what could the gas be? Sulfur dioxide? I don't think that has nitrogen in it.

 

[m25]

First, it's not nitric acid that's doing anything. Nitric acid doesn't even exist in high concentration. It's the nitrate anion doing the cool stuff cause nitrate ion is what you have in the system mainly. You know from the data table; the nitric acid solution tends to oxidize metals vigorously or violently.

Okay so I realized that my understand was totally off.
So which one is the oxidizing agent in:

a) HCl? H+ or Cl-? My guess is that H+ is the oxidizing agent since H2 bubble forms according to question 2. But without question, how am I supposed to know this?

b) H2SO4? H+, SO4-2, or HSO4-1? The answer to #2 states that SO4-2 is not a better oxidizing agent than H+, but how do I know this? Also, according the table, is H+ the slightly more powerful oxidizing agent than SO2-4 since all their results are the same except for iron and aluminum, and comparing these two, we cancel out the two M's on both side and is left with V for HCl and S for H2SO4?


Why would have you have to know this? If nitrate anion is the oxidizing agent, what could the gas be? Sulfur dioxide? I don't think that has nitrogen in it.

okay, then how do you know it's not nitrogen or ammonia?

Thank you so much!!

 

[Teleologist]

okay, then how do you know it's not nitrogen or ammonia?

Thank you so much!!

Ammonia sure doesn't have a color; you should have used ammonia by now either at home or in lab. N2 is the most abundant component of air (about 7% of air is N2).

 

[m25]

Oops, my first question accidentally got incorporated into the quote so here it is again:

Okay so I realized that my understand was totally off.
So which one is the oxidizing agent in:

a) HCl? H+ or Cl-? My guess is that H+ is the oxidizing agent since H2 bubble forms according to question 2. But without question, how am I supposed to know this?

b) H2SO4? H+, SO4-2, or HSO4-1? The answer to #2 states that SO4-2 is not a better oxidizing agent than H+, but how do I know this? Also, according the table, is H+ the slightly more powerful oxidizing agent than SO2-4 since all their results are the same except for iron and aluminum, and comparing these two, we cancel out the two M's on both side and is left with V for HCl and S for H2SO4?