Acids and Bases Flashcards
Types of solution
Strong acid, strong base, weak acid , weak base
What is a buffer
A buffer is a solution that can resist changes to pH when small amounts of H+ /OH- to regulate pH
Types of buffer
- Acidic buffer
- WA, CB
- pH= pKa + lg( [CB]/[WA])
2.Alkaline buffer
-WB, CA
-pH= pKa + lg([CA]/[WB])
Acidic salt
CA
[H+] = (Ka x [WA])^1/2
Basic salt
CB
[OH-] = (Kb x [WB])^1/2
Ionic dissociation of water
Kw = [H+][OH-]
pKw = pOH +pH =14
pOH+pH=14
Kw = Ka x Kb
pH
-lg[H+]
[H+] = 10^(-pH)
pOH
-lg[OH-]
[OH-] = 10^ (-pOH)
Lewis acid/base
Acid
Electron pair acceptor
(due to vacant low-lying vacant orbital which is energetically accessible to accept electron pair)
e.g. BH3
Base
Electron pair donor
e.g. NH3
Bronsted lowry acid/base
Acid
H+ donor
e.g. HCl
Base
H+ acceptor
NaOH/ NH3
Arrhenius
Acid
dissociates/protonates in water to give H+
Base
dissociates/deprotonates in water to give OH-
Strong acid/base
ionise completely
Weak acid/base
ionise partially
Titration curve
3 regions
1. b4 eqv pt/ buffer pt if SB/A is added slowly to WA/WB
2.eqv pt salt is formed and WA/WB/SB/WA in limiting has completely reacted
3. after eqv point/ buffer pt if WA/B slowly added to SB/A
Initial
a) pH= pH of SB/A or WB/A in conical flask
At buffer region
- MBC
a) pH= pKa
b) vol= 1/2 or 2 x Vneut (at eqv pt)
At eqv pt
a) pH=pH of salt
b) acidic salt hydrolysise to give pH<7
c) basic salt hydrolysise to give pH>7
d) WA+SB= basic salt (conjugate base)
e) WB+SA = acidic salt (conjugate acid)
Conjugate base
has 1 less H+ than the acid
