pH question..^^

[license2kill]

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It has been a year since I wrote the DAT, so I am a little rusty on Chemistry. (My friend and I have a bet.)

0.01 NaNO3 solution
pH?

I reasoned that sodium nitrate dissociates into Na+ and nitrate.
I then reasoned...

NO3- + H2O --> HNO3 + OH-

But then I reasoned that HNO3 cannot be formed due to the definition of a strong acid COMPLETELY dissociating hence cannot even form.

Thus, pH = 7.

What do you guys think?
Am I wrong? Please do comment.^^

 

[nze82]

It has been a year since I wrote the DAT, so I am a little rusty on Chemistry. (My friend and I have a bet.)

0.01 NaNO3 solution
pH?

I reasoned that sodium nitrate dissociates into Na+ and nitrate.
I then reasoned...

NO3- + H2O --> HNO3 + OH-

But then I reasoned that HNO3 cannot be formed due to the definition of a strong acid COMPLETELY dissociating hence cannot even form.

Thus, pH = 7.

What do you guys think?
Am I wrong? Please do comment.^^

pH would be equal to 7, but not for the reason you mentioned.
NaNH3 dissociates into Na+ and NO3-. Then, each component reacts with water to produce NaOH (Strong Base) and HNO3 (Strong Acid), and of course a mixture of a strong acid and a strong base leads to a neutralization reaction, which produces water. Hence, the final pH = 7.

 

[loveoforganic]

Uh, still not really it. NO3- is such a poor base and Na+ is such a weak acid that essentially no protonation/deprotonation beyond the autoionization of water even takes place.

"But then I reasoned that HNO3 cannot be formed due to the definition of a strong acid COMPLETELY dissociating hence cannot even form."

That reasoning was right.

 

[license2kill]

So I was right or not?
I agree with the third post, NaOH and HNO3 will not even form in the first place, thus no neutralization rxn even occurs.

I was arguing with a suma cum laude chemistry major and another chemistry major with 4.0 GPA, they both reasoned that the pH would be a tidbit over 7, but I still think that there is a big difference in argument since that would mean that there is some formation of HNO3 in the first place.

Anyways, thanks for the backup either way- I still get my beers~!

Cheers~!🙂

 

[license2kill]

So I was right or not?
I agree with the third post, NaOH and HNO3 will not even form in the first place, thus no neutralization rxn even occurs.

I was arguing with a suma cum laude chemistry major and another chemistry major with 4.0 GPA, they both reasoned that the pH would be a tidbit over 7, but I still think that there is a big difference in argument since that would mean that there is some formation of HNO3 in the first place.

Anyways, thanks for the backup either way- I still get my beers~!

Cheers~!🙂

 

[joonkimdds]

So I was right or not?
I agree with the third post, NaOH and HNO3 will not even form in the first place, thus no neutralization rxn even occurs.

I was arguing with a suma cum laude chemistry major and another chemistry major with 4.0 GPA, they both reasoned that the pH would be a tidbit over 7, but I still think that there is a big difference in argument since that would mean that there is some formation of HNO3 in the first place.

Anyways, thanks for the backup either way- I still get my beers~!

Cheers~!🙂

I am a magna cum(ewww) laude biology major and I think pH = 7.001

 

[loveoforganic]

Technically, sodium is a stronger acid than nitrate is a base, so you'd end up with a pH very slightly less than 7. The value is incredibly tiny though. There's always an acid/base equilibrium, and technically some nitric acid and some (a slightly larger amount) sodium hydroxide would form for a brief instant, very temporarily decreasing the pH. The equilibrium constants of those equilibria are just obscenely small however.

 

[nze82]

So I was right or not?
I agree with the third post, NaOH and HNO3 will not even form in the first place, thus no neutralization rxn even occurs.

I was arguing with a suma cum laude chemistry major and another chemistry major with 4.0 GPA, they both reasoned that the pH would be a tidbit over 7, but I still think that there is a big difference in argument since that would mean that there is some formation of HNO3 in the first place.

Anyways, thanks for the backup either way- I still get my beers~!

Cheers~!🙂

Even if you're still not sure about the correct explanation, you know that you got the right pH. So, make him pay up!!

 

[doc toothache]

Salts of strong acids and strong bases are neutral.