pH, Ka and pKa Flashcards
1
Q
pH
A
conc of H+ ions
2
Q
pH calc
A
= -log[H+]
3
Q
Ka
A
acid dissociation constant- how readily [H+] ions dissociate
4
Q
equation for Ka relates to
A
HA —-> H+ + A-
5
Q
equation for Ka
A
ka= [H+] [A-] / [HA]
6
Q
the stronger the acid the higher the conc of
A
[H+] and [A-]
7
Q
the weaker the acid the higher the one of
A
HA
8
Q
pKa
A
is the pH at which 50% of the drug is ionised and 50% of the drug is not ionised
9
Q
calc for pKa
A
= -logKa
10
Q
PL
A
isoelectric point
11
Q
isoelectric point
A
pH at which no int charge
12
Q
a large Ka
A
stronger acid
13
Q
a small Ka
A
weaker acid
14
Q
a large pKa
A
weaker acid
15
Q
a small pKa
A
stronger acid
16
Q
Ka and pKa are
A
inversely related
17
Q
the smaller the pKa (stronger acid), the
A
more ionised and therefore hydrophobic- will not pass cell membrane easily
18
Q
Henderson- hasselbach equation
A
pH= pKa + Log (A-/HA)
