2006-06-05 19:56:35 · 13 answers · asked by 23212 1 in Science & Mathematics ➔ Chemistry
Taste it.
2006-06-05 19:57:52 · answer #1 · answered by Anonymous · 4⤊ 10⤋
Pka Equation
2016-10-04 10:41:03 · answer #2 · answered by ? 4 · 0⤊ 0⤋
How about a worked example?
The pH of a weak acid, HA of concentration 0.100mol dm^-3 was found to be 4.00. Calculate the value of the pKa for the acid.
If the pH is 4.00, then [H+] = 1.00 X 10^-4 mol dm^-3
So start by writing the equation
HA (aq) -----> H+ (aq) + A- (aq)
Start conc 0.100 0 0
Equilibirum conc HA= 0.100-1.00 x 10^-4 H+=1.00 x 10^-4 A-=1.00 x 10^-4
= 0.0999
Ka = [H+][A-]
[HA]
=(1.00 x 10^-4)^2
0.0999
= 1.001 x 10^-7 mol dm^-3
pKa = -log10 Ka
= 7.00
That would be your answer. I hope this helped. It took me a while to get round to remembering it. I tried to put it in a way you could understand it, but there are no division lines, so just compensate.
Good Luck!
2006-06-06 00:20:15 · answer #3 · answered by bilahboo 1 · 3⤊ 0⤋
This Site Might Help You.
RE:
how do you determine pKa of an acid?
2015-08-06 08:55:31 · answer #4 · answered by Anonymous · 0⤊ 0⤋
A few methods.
Conductivity (with a voltameter)
Titration (Acid/Base) with the Henderson/Hasselbach equation
In my physical chemistry class, and I know I've said this before, we determined pKa of a nitrogen heterocycle with a technique called NMR, because the sample being protonated and unprotonated caused a variance in the chemical shift, which could be detected.
2006-06-06 06:12:45 · answer #5 · answered by niuchemist 6 · 1⤊ 0⤋
The ionisation of the acid is measured by measuring its conductivity. This data is the used to determine Ka and hence pKa.
2006-06-05 19:59:29 · answer #6 · answered by ag_iitkgp 7 · 0⤊ 0⤋
it is the negative log of hydrogen ion concentration to the base ten
pka = -log10[H+]
lower the value of pka, higher will be the acidity of it.(as there is a -ve sign)
2006-06-05 20:46:51 · answer #7 · answered by ciute 2 · 1⤊ 0⤋
thre was a formula for calculating pka
2006-06-05 19:58:40 · answer #8 · answered by Mrinal 2 · 0⤊ 0⤋
use this formula
pKa = - log [H+]
where, [H+] is the concentration of proton in the acid solution
2006-06-05 20:04:35 · answer #9 · answered by mimi 2 · 0⤊ 0⤋
Please see the webpages for more details on pKa. Acid Disossiation Constant.-Honesly speaking, I find it more difficult to understand.
2006-06-05 20:12:19 · answer #10 · answered by gangadharan nair 7 · 1⤊ 1⤋
read vogel man
2006-06-05 20:11:34 · answer #11 · answered by Raju.K.M 5 · 0⤊ 0⤋