Post by: vizakenjack on December 07, 2014, 08:08:31 PM
So uhm... why aren't there any?
Post by: billnotgatez on December 07, 2014, 09:51:38 PM
Please read forum rules
You can click on the link near the top of the page
Forum Rules: Read This Before Posting
Post by: vizakenjack on December 07, 2014, 10:53:25 PM
We are a teaching forum here and forum rules require you show some work.This isn't a problem that requires calculation... or steps... it's a concept question... I guess.
So I dunno what you're nagging about... ::)
HCl give off a cation H+ and an anion Cl-. So cations CAN come from acids...
Post by: kriggy on December 08, 2014, 03:13:26 AM
http://en.wikipedia.org/wiki/Lewis_acids_and_bases
What are features of acids and bases?
Post by: vizakenjack on December 08, 2014, 06:34:41 PM
What are features of acids and bases?Why can't you just answer the question -.- ...
Acid donates a proton (H)
Base accepts it...
and?
Post by: Borek on December 09, 2014, 02:54:14 AM
What are features of acids and bases?Why can't you just answer the question -.- ...
You were asked to THINK about why, have you tried?
Quote
Acid donates a proton (H)
Base accepts it...
and?
Good, now try to write a reaction that the Basic cation would undergo. Does it look reasonable, or not? Why yes, why not?
Post by: vizakenjack on December 09, 2014, 05:43:33 PM
Good, now try to write a reaction that the Basic cation would undergo. Does it look reasonable, or not? Why yes, why not?What kind of a reaction?
Like, the amphiprotic (donates/accepts H+) sulfuric acid?
HSO4 + H2O -> H3O+ + SO4+
or
HSO4 + H2O -> OH- + H2SO4
Detailed ionic would look like this? (I thought you can only write them for salts... but whatever):
H+ + SO4- + H2O ...
?
Cation H+ reacts in both cases, so...?
Post by: Borek on December 09, 2014, 06:28:02 PM
Good, now try to write a reaction that the Basic cation would undergo. Does it look reasonable, or not? Why yes, why not?What kind of a reaction?
Reaction that is responsible for the fact ions/substances listed in the table are classified as basic or acidic. That's what the question is about.
Post by: Irlanur on December 11, 2014, 10:17:42 AM
Post by: clarkstill on December 11, 2014, 01:27:48 PM
![[NH3+]CN](https://www.chemicalforums.com/SMILES/93a5c0edf3275b2d346b.png)
Surely at a sufficiently low pH the second amine will protonate? Surely this is the precise analogue of the HSO4- etc. used as examples of "acidic anions"?
Post by: Borek on December 11, 2014, 02:42:52 PM
Why can you have acidic anions and not basic cations?
That's what the question is about.
You are not completely off with your thinking, but you are ignoring an important difference which makes things interesting. Think about size.
Post by: clarkstill on December 12, 2014, 01:26:21 AM
Why can you have acidic anions and not basic cations?
That's what the question is about.
You are not completely off with your thinking, but you are ignoring an important difference which makes things interesting. Think about size.
Size matters not. Are you really saying that at pH -50 the molecule I drew wouldn't be protonated on both nitrogens? The fact it might cleave a la acetal might make it practically a bad idea, but in theory there is nothing preventing it.
Post by: Borek on December 12, 2014, 03:00:11 AM
Size matters not. Are you really saying that at pH -50 the molecule I drew wouldn't be protonated on both nitrogens? The fact it might cleave a la acetal might make it practically a bad idea, but in theory there is nothing preventing it.
Straw man. I never said diamine can't be doubly protonated.
Besides, while the negative pH is possible, pH of -50 is definitely not. Throwing random numbers around is not a best way of arguing your point.
As I said many posts earlier, we should start with a reaction equation.
Post by: Dan on December 12, 2014, 03:26:54 AM
If a base can be doubly protonated, surely there is a basic cation. What about hydrazine - both the mono- and dihydrochlorides are commercially available?
Post by: Borek on December 12, 2014, 06:01:19 AM
From the content of the table posted in the original question I think it refers not to large, organic cations, but to small, inorganic ones.
Post by: billnotgatez on December 12, 2014, 06:26:27 AM
Quote
I think it refers not to large, organic cations, but to small, inorganic ones
CH3COO-
Anion of week acid
Was not enough to change your assumption?
just asking
Post by: Dan on December 12, 2014, 09:47:31 AM
I think it refers not to large, organic cations, but to small, inorganic ones.
I'm sure this is indeed the case, nevertheless: the hydrazinium cation is basic, inorganic and small...
Post by: mjc123 on December 12, 2014, 11:04:08 AM