Aren't bases compounds that produce hydroxide ions when dissolved in water? But there ARE no hydroxide ions in NaHCO3? I tried googling it, but I didn't understand the explanations.. Can someone explain it in the simplest way possible? It's grade 10 science.
I also had an example in my note that says Mg(OH)2 -> [Mg]+2 plus [OH]- (the + and the - are the charges)... So if you were to do that with NaHCO3 what would it look like?
NaHCO3 -> ....?
I was thinking NaHCO3 -> Na+HCO3 ?
But that just seems wrong... And if it was a base it would have to have hydroxide on the right side, wouldn't it?
I don't know if my understanding of this is all just completely off, or what...
Thanks in advance.
I also had an example in my note that says Mg(OH)2 -> [Mg]+2 plus [OH]- (the + and the - are the charges)... So if you were to do that with NaHCO3 what would it look like?
NaHCO3 -> ....?
I was thinking NaHCO3 -> Na+HCO3 ?
But that just seems wrong... And if it was a base it would have to have hydroxide on the right side, wouldn't it?
I don't know if my understanding of this is all just completely off, or what...
Thanks in advance.
-
NaHCO3 can sometimes act as a base because, as you have indicated, when NaHCO3 dissociates in water it forms HCO3- ions. HCO3- ions are one of those ions that are called AMPHOTERIC IONS.
If you look on an acid-base reaction table you will find that H2CO3 is called carbonic acid. It is a weak acid because when it is put in water it dissociates into H+ ions and HCO3- ions
H2CO3 <----------------> H+ + HCO3-. Notice that this is a reversible reaction? If HCO3- ions are floating around in water they can combind with any extra H+ ions to form H2CO3. So HCO3- in that case is acting as a base. Bronsted-Lowry theory says that not all bases have to contain OH- ions. Some substances can act as a base if they are willing to ACCEPT an H+ ion.
On the other hand HCO3- can act as an acid if it is combined with a strong base like NaOH
In that case you would get: OH- + HCO3- ----------------> HOH + CO3-2. That is why HCO3- is AMPHOTERIC, it can act as either acid or base, depending upon what it is reacted with.
If you look on an acid-base reaction table you will find that H2CO3 is called carbonic acid. It is a weak acid because when it is put in water it dissociates into H+ ions and HCO3- ions
H2CO3 <----------------> H+ + HCO3-. Notice that this is a reversible reaction? If HCO3- ions are floating around in water they can combind with any extra H+ ions to form H2CO3. So HCO3- in that case is acting as a base. Bronsted-Lowry theory says that not all bases have to contain OH- ions. Some substances can act as a base if they are willing to ACCEPT an H+ ion.
On the other hand HCO3- can act as an acid if it is combined with a strong base like NaOH
In that case you would get: OH- + HCO3- ----------------> HOH + CO3-2. That is why HCO3- is AMPHOTERIC, it can act as either acid or base, depending upon what it is reacted with.