• Funniest Story on the Job Contest Starts Now!

    Contest starts now and ends September 27th. Winner will receive a special user banner and $10 Amazon Gift card!

    JOIN NOW
  • Site Updates Coming Next Week

    Site updates are coming next week on Monday and Friday. Click the button below to learn more!

    LEARN MORE

Ex 4.4 tbr acid and base

Meredith92

Full Member
7+ Year Member
Aug 29, 2012
513
107
216
  1. Medical Student
Im not sure how tbr arrived at this answer unless they expect us to memorize lots of pKa values

Which of the following acids dissociates to the greatest extent when added to water
A. HNO3
B HNO2
C H3PO4
D H2CO3

The answer is a
But when drawing the structures out it seems that HNO3 would not "want" to have a proton removed because it would create more charge. Should I have chosen a anyway because it has one more resonance form despite the extra charge? I'm never sure how to approach these questions :/ thanks for your help!
 

gettheleadout

MD
Moderator Emeritus
10+ Year Member
Jun 23, 2010
11,808
2,801
276
  1. Resident [Any Field]
But did you know hno3 was a strong acid just from memorizing it? If I didn't have that memorized how would I know hno3 is a strong acid since losing a proton makes it carry more charge?

1) You should absolutely memorize the strong acids: HNO3, H2SO4, HClO4, HClO3, HBr, HCl, and HI.

2) The negative charge gained upon deprotonation is stabilized via resonance within the nitrate anion, and is quite stable in aqueous solution. Further, many, many acids (all of the strong ones) gain a negative charge upon ionization (hence the term "ionization"). The only example I can think of off the top of my head that instead becomes neutral is ammonium (NH4+), and ammonium is a weak acid.
 
About the Ads

Meredith92

Full Member
7+ Year Member
Aug 29, 2012
513
107
216
  1. Medical Student
Okay thanks that makes sense

I just feel like I'm abandoning my organic chemistry knowledge by accepting that having a positive charge on N ( which is electronegative) and having TWO negative charges is a good structure. For HNO3 to be a strong acid it's conjugate base should be stable/ have a decent structure... And it's hard for me to easily grasp why this works well. I guess the additional resonance structure makes up for these bad charge placements
 
This thread is more than 8 years old.

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.