Salts of Strong Base/Strong Acid

[MedPR]

So Na2O is the sale of NaOH, right? Why is Na2O a strong base (according to EK 1001 Gen Chem 746)?

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[chiddler]

Think of what happens when both sodiums dissociate.

O(2-) forms. Then it reacts. OH(-) forms. Still strong. Then H2O.

All strong bases.

O(2-) probably doesn't form though. more likely 2 NaOH's.

 

[gettheleadout]

So Na2O is the sale of NaOH, right? Why is Na2O a strong base (according to EK 1001 Gen Chem 746)?

The salt of a strong acid and strong base will always be neutral. Na2O is the salt of NaOH and what acid? It definitely isn't a strong acid. Na2O can't be the salt of just NaOH, either, since the equilibrium for aqueous NaOH is:

NaOH + H2O <---> Na+ + OH- + H2O

 

[MedPR]

I'm still lost. How is Na2O a strong base?

 

[gettheleadout]

I'm still lost. How is Na2O a strong base?

Well look at the components of the salt. Na+ is the conjugate of NaOH, so you know it won't react in solution when the Na2O dissociates, but the O2- is one of the strongest bases there is. It will snatch up a hydrogen quicker than anything else to form OH-.

 

[MedPR]

Well look at the components of the salt. Na+ is the conjugate of NaOH, so you know it won't react in solution when the Na2O dissociates, but the O2- is one of the strongest bases there is. It will snatch up a hydrogen quicker than anything else to form OH-.

I guess I'm confused about why the oxygens would rather have hydrogens than nitrogens? Both are +1 cations, so what makes hydrogen more attractive?

 

[gettheleadout]

I guess I'm confused about why the oxygens would rather have hydrogens than nitrogens? Both are +1 cations, so what makes hydrogen more attractive?

You mean sodium? Well if the oxygen bonds with sodium you have an ionic bond (which is all salt means) which is soluble in aqueous solution, so the O won't stay bonded to Na2 for very long (if this weren't the case then salts wouldn't ever be able to affect solution pH.) The alternative is the O2- bonds to a free H+ or pulls one off of an H2O, in which case the covalent O-H bond formed is very unlikely to break.

 

[MedPR]

You mean sodium? Well if the oxygen bonds with sodium you have an ionic bond (which is all salt means) which is soluble in aqueous solution, so the O won't stay bonded to Na2 for very long (if this weren't the case then salts wouldn't ever be able to affect solution pH.) The alternative is the O2- bonds to a free H+ or pulls one off of an H2O, in which case the covalent O-H bond formed is very unlikely to break.

Yea, I meant sodium, not nitrogen.

Forgot about the ionic bond. Thanks!