NaNO3 is not a base?

[johnwandering]

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Because HNO3 was a strong acid, i was under the impression that NaNO3 was a weak base.

But apparently its just a neutral salt and not a base at all?


This is fairly confusing because i thought conjugates of strong acids were weak bases....

 

[MedPR]

The conjugate base of HNO3 is NO3-, not NaNO3.

What is NaCl? A base, or a salt? NaNO3 is the same thing, just with a different anion.

 

[SaintJude]

Don't forget NaOH is a strong base

Strong Base + Strong Acid---> neutral salt

 

[johnwandering]

Whoa, waittt.
I'm really sorry but Acid/Base has always been one of my weakest subjects. I am soooo confused right now.


We are saying that NaNO3 is NOT a conjugate of HNO3?
In problem 94 chapter 4 of BR, it states that KF is a conjugate of HF.

Are we also saying that NaNO3 is NOT a base, but Na+ NO3- is a base?



Sorry I'm confused because I know that NaOH, NaNH2 are all strong bases that are just written as: Na+ OH- and Na+ NH2-

Why is NaNO3 NOT Na+ NO3- ?


Does pKa have to be negative in order for use to consider a NaX as Na+ X-??




I have been on Acid/Base for nearly 4 days now and I cannot get my head around all this...
I have to be misunderstanding something....

 

[johnwandering]

Strong Base + Strong Acid---> neutral salt

Also, but this standard, does this mean that the statement

Strong acid-----> Weak Base
Strong Base-----> Weak Acid

is false?

 

[MedPR]

Whoa, waittt.
I'm really sorry but Acid/Base has always been one of my weakest subjects. I am soooo confused right now.


We are saying that NaNO3 is NOT a conjugate of HNO3?
In problem 94 chapter 4 of BR, it states that KF is a conjugate of HF.

Are we also saying that NaNO3 is NOT a base, but Na+ NO3- is a base?



Sorry I'm confused because I know that NaOH, NaNH2 are all strong bases that are just written as: Na+ OH- and Na+ NH2-

Why is NaNO3 NOT Na+ NO3- ?


Does pKa have to be negative in order for use to consider a NaX as Na+ X-??




I have been on Acid/Base for nearly 4 days now and I cannot get my head around all this...
I have to be misunderstanding something....

A base is something that donates an electron pair. What electron pair is NaNO3 going to donate?

NO3- has an electron pair to donate.

HF is a weak acid. Strong base + strong acid = salt. Weak acid + strong base =/= salt.

 

[johnwandering]

Strong base + strong acid = salt. Weak acid + strong base =/= salt.

Thanks this really helps.


I thought that NaNO3 was just Na+ NO3-? and hence NO3- would have the electrons to donate...

If it is NOT a strong acid/base, then we DO NOT notate them as separate ions?

 

[chiddler]

NO3(-) is a conjugate base of HNO3. NaNO3 is technically not the conjugate but forms the conjugate when it dissociates.

NO3(-) is not a base at all regardless of which cation is added to it. The reason it is not a base is because a (bronstead) base is characterized as something that increases the pH by accepting protons, removing them from solution. My question to you is would NO3(-) accept protons and form HNO3? I'll remind you that HNO3 is a strong acid.

 

[MedPR]

Thanks this really helps.


I thought that NaNO3 was just Na+ NO3-? and hence NO3- would have the electrons to donate...

If it is NOT a strong acid/base, then we DO NOT notate them as separate ions?

As far as I know, NaNO3 is no different than Na+NO3-. Adding in the +/- is just to help you see where the electron density lies. Once NO3- binds up with a counterion, like Na+, it is no longer a base and is now a salt. If Na+NO3- were to donate an electron pair somewhere, either the central nitrogen, or one of the oxygens would have an extra bond and would be very unhappy. That's not going to happen.

 

[johnwandering]

NO3(-) is not a base at all regardless of which cation is added to it. The reason it is not a base is because a (bronstead) base is characterized as something that increases the pH by accepting protons, removing them from solution. My question to you is would NO3(-) accept protons and form HNO3? I'll remind you that HNO3 is a strong acid.

Sorry I had learned that
Strong acid--------------> Weak base.

I'm having a hard time completely unlearning this rule/learning where to apply it.
Why exactly does this rule not apply here? As in, because NO3 not a base at all..

 

[MedPR]

Sorry I had learned that
Strong acid--------------> Weak base.

I'm having a hard time completely unlearning this rule/learning where to apply it.
Why exactly does this rule not apply here?

It does apply. HNO3 is a strong acid, and NO3- is its weak conjugate base. Once you toss on the Na+, forming NaNO3, you have made a salt.

 

[MedPR]

NO3(-) is a conjugate base of HNO3. NaNO3 is technically not the conjugate but forms the conjugate when it dissociates.

NO3(-) is not a base at all regardless of which cation is added to it. The reason it is not a base is because a (bronstead) base is characterized as something that increases the pH by accepting protons, removing them from solution. My question to you is would NO3(-) accept protons and form HNO3? I'll remind you that HNO3 is a strong acid.

Why isn't NO3- a base? Are you saying that HNO3 doesn't have a conjugate base?

NO3- can accept a proton, making it a bronsted base. It can also donate a pair of electrons, making it a lewis base.

 

[johnwandering]

Why isn't NO3- a base? Are you saying that HNO3 doesn't have a conjugate base?

Thanks that helps.

Sooooooooooo NO3- is a base, and becomes neutralized once turned into salt.....

 

[johnwandering]

Sooo, to recap...



STRONG Acids/Bases are Allowed to be notated as salts:
NaOH
NaNH2


But WEAK Acids/Bases are NOT allowed to be notated as salts
because that means that they are neutralized?

 

[MedPR]

Sooo, to recap...



STRONG Acids/Bases are Allowed to be notated as salts:
NaOH
NaNH2


But WEAK Acids/Bases are NOT allowed to be notated as salts
because that means that they are neutralized?

You can notate it anyway you want. Take sodium acetate.

Acetate ion is a weak base. Sodium acetate is NaOAc, or CH3COONa.

 

[chiddler]

Why isn't NO3- a base? Are you saying that HNO3 doesn't have a conjugate base?

NO3- can accept a proton, making it a bronsted base. It can also donate a pair of electrons, making it a lewis base.

Sorry I should of said is not basic. It is the conjugate base form, for sure.

 

[johnwandering]

Thanks guys for bearing with me. I really really appreciate it. A million times over.
especially MedPr

So is this just a case where NO3- is just soooo weak as a base that it won't even dissociate from the Na+.



So, to better refine my term:

Conjugates of weak acids/bases can be notated with a salt.

Conjugates of Strong Acids/Bases, if notated with a salt, are neutral and no longer acid/base.

 

[MedPR]

Thanks guys for bearing with me. I really really appreciate it. A million times over.
especially MedPr

So is this just a case where NO3- is just soooo weak as a base that it won't even dissociate from the Na+.



So, to better refine my term:

Conjugates of weak acids/bases can be notated with a salt.

Conjugates of Strong Acids/Bases, if notated with a salt, are neutral and no longer acid/base.

Yes, if you can remember that strong acid+strong base = salt + water, you'll be golden.

 

[ipodtouch]

From the scope of this topic, I think the OP is just asking:


Why can CH3COONa be written as a salt and still be a base of ions:
(CH3COO)- (Na)+
And why can't NaNO3 be written as a salt and be a base of ions:
(Na)+ (NO3)-



I believe it's because NO3- is too weak of a base that it cannot dissociate from Na+?
Does anyone know if there is a pKa/pKb cut off for when an a or b can no longer exist as separate ions in a salt?

 

[MedPR]

From the scope of this topic, I think the OP is just asking:


Why can CH3COONa be written as a salt and still be a base of ions:
(CH3COO)- (Na)+
And why can't NaNO3 be written as a salt and be a base of ions:
(Na)+ (NO3)-



I believe it's because NO3- is too weak of a base that it cannot dissociate from Na+?
Does anyone know if there is a pKa/pKb cut off for when an a or b can no longer exist as separate ions in a salt?

I don't know if there is a cutoff, but for the MCAT there are 6 strong acids:

HClO4
HI
HBr
HCl
HNO3
H2SO4

And a bunch of strong bases. Mostly the group 1 metal hydroxides.

Anytime a strong base and strong acid react, they form a neutral salt and water. So if you see a ClO4, I, Br, Cl, NO3, HSO4 salt, you know it is neutral.

 

[johnwandering]

Oh wow thanks!


Final Question (I promise):

We keep saying Strong acid +Strong Base. But it seems that

HNO3 + CH3COONa ------------> NaNO3 + CH3COOH

as well~



So should the statement be modified to say:

Anytime a strong acid/base react with ANY A/B of any strength, they will form a neutral salt?


Because it seems like you still get the same neutral salt even if the original base isn't strong at all.

 

[MedPR]

Oh wow thanks!


Final Question (I promise):

We keep saying Strong acid +Strong Base. But it seems that

as well~



So should the statement be modified to say:

Anytime a strong acid/base react with ANY A/B of any strength, they will form a neutral salt?


Because it seems like you still get the same neutral salt even if the original base isn't strong at all.

No

HF + KOH ---> KF + H2O

KOH is a strong base, HF is a weak acid, KF isn't a neutral salt.

 

[johnwandering]

Oh sorry, I meant strictly

the conjugate of the strong acid/base becomes neutral in any acid/base reaction


Which seems to be the case because the conjugate weak acid of K+OH- has become H2O~

 

[MedPR]

Oh sorry, I meant strictly

the conjugate of the strong acid/base becomes neutral in any acid/base reaction


Which seems to be the case because the conjugate weak acid of K+OH- has become H2O~

I can't think of any examples to prove you wrong, but I don't know that you are right either.

I'd stick with writing out the products just to be sure.