Chemical Forums

Please login or register.

Login with username, password and session length

Sponsored links

Pages: [1]   Go Down

Author Topic: Nitric acid  (Read 22089 times)

0 Members and 1 Guest are viewing this topic.

Anson

  • Guest
Nitric acid
« on: April 13, 2005, 03:26:53 AM »

What is the Acid Dissociation Constant Ka for nitric acid?
Logged

jdurg

  • Banninator
  • Retired Staff
  • Sr. Member
  • *
  • Mole Snacks: +106/-21
  • Offline Offline
  • Gender: Male
  • Posts: 1363
  • I am NOT a freak.
Re:Nitric acid
« Reply #1 on: April 13, 2005, 03:46:23 AM »

VERY, VERY, VERY HIGH.  Nitric Acid is a very strong acid and for all intents and purposes completely dissociates upon dissolution in water.
Logged
"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists

Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Mole Snacks: +1370/-369
  • Offline Offline
  • Gender: Male
  • Posts: 20981
  • I am known to be occasionally wrong.
    • Chembuddy
Re:Nitric acid
« Reply #2 on: April 13, 2005, 04:39:25 AM »

Logged
Chembuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

jdurg

  • Banninator
  • Retired Staff
  • Sr. Member
  • *
  • Mole Snacks: +106/-21
  • Offline Offline
  • Gender: Male
  • Posts: 1363
  • I am NOT a freak.
Re:Nitric acid
« Reply #3 on: April 13, 2005, 04:55:58 AM »

But those are pKa values and are even stated to be 'not so accurate'.   ;D  Here's a pretty good table and you can see that the Ka of Nitric Acid is 24.  Yes it's not insanely high, but compare that with the Ka of acetic or oxalic acid and it's substantially higher.  ;D
Logged
"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists

Garneck

  • Guest
Re:Nitric acid
« Reply #4 on: April 13, 2005, 06:40:22 AM »

But those are pKa values and are even stated to be 'not so accurate'.   ;D  Here's a pretty good table and you can see that the Ka of Nitric Acid is 24.  Yes it's not insanely high, but compare that with the Ka of acetic or oxalic acid and it's substantially higher.  ;D

So that means pKa for nitric acid is -1,38. Is that high?
Logged

Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Mole Snacks: +1370/-369
  • Offline Offline
  • Gender: Male
  • Posts: 20981
  • I am known to be occasionally wrong.
    • Chembuddy
Re:Nitric acid
« Reply #5 on: April 13, 2005, 12:41:33 PM »

But those are pKa values and are even stated to be 'not so accurate'.

I know, I wrote it by myself :)

Quote
Ka of Nitric Acid is 24.

Which is - as Garneck already stated - not far from the value in my table.

Quote
Yes it's not insanely high, but compare that with the Ka of acetic or oxalic acid and it's substantially higher.

Yes, but when compared with HClO4 or HCl it is substantially weaker. Nitric acid is probably the weakest of the strongest :)

Logged
Chembuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

hmx9123

  • Retired Staff
  • Full Member
  • *
  • Mole Snacks: +59/-18
  • Offline Offline
  • Posts: 887
Re:Nitric acid
« Reply #6 on: April 14, 2005, 09:08:41 PM »

http://daecr1.harvard.edu/pka/InorganicAcids.GIF

That's the table from Evan's Harvard class.  It's probably decently accurate.

If you want a nice strong acid, why not try 'magic acid'? (This is NOT the kind of magic acid that limpet likes)
Logged

Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Mole Snacks: +1370/-369
  • Offline Offline
  • Gender: Male
  • Posts: 20981
  • I am known to be occasionally wrong.
    • Chembuddy
Re:Nitric acid
« Reply #7 on: April 14, 2005, 11:07:16 PM »

http://daecr1.harvard.edu/pka/InorganicAcids.GIF

That's the table from Evan's Harvard class.  It's probably decently accurate.

Thanks, there were a few that I haven't seen before.

However, I feel like I wan't to add my $.02.

I am observing these constants in various sources for about 20 years now. In most cases they were masured two or three times and results were similar - something like  -1.3, -1, -1.4 - and they are now quoted again and again, in most cases nobody knows what was the original source and why this or that particular value is better then others. Sometimes sources are quoted but they are often from fifties or even earlier and difficult to check now.

This is not the whole truth at the far end - like HI or HClO4 - where accuracy of measurements is much lower. If the solution is diluted enough to avoid activitiy problems concentration of undissolved acid is often unmeasurable. If the solution is concentrated, activity effects start to play important role and it is not easy to interpolate the results for zero ionic strength.
Logged
Chembuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info
Pages: [1]   Go Up
 

Mitch Andre Garcia's Chemical Forums 2003-Present.

Page created in 0.081 seconds with 23 queries.