Acids formed from anions with names that end in ide
Ex. Halogens
Prefix: hydro
ending: ic
Chloride:
Hydrochloric acid
If the anion ends in ite (less oxygen)
-ous acid
If the anion ends in -ate (more oxygen)
-ic acid
Autoionization of water
H2O (l) + H2O (l) ------->
H3O+ (aq) + OH- (aq)
Water dissociation constant Kw
Kw = [H3O+] [OH-]
= 10-14 @ 25 C (298K)
pH
pH= -log[H+]
pOH
pOH= -log[OH-]
pH+pOH=
14
p value
-log (n x 10-m)= -log(n) - log (10-m)
= m - 0.n
pH=7= neutral is only valid at 25C
Kw like any other equilibrium constant, is dependent only
on temperature.
Isolated changes in concentration, pressure, or volume will not
affect Kw
Strong acids
HCl (Hydrochloric acid)
HBr (Hydrobromic acid)
HI (Hydroiodic acid)
H2SO4 (Sulforic acid)
HNO3 (Nitric acid)
HClO4 (Perchloric acid)
Strong base
NaOH (sodium hydroxide)
KOH (potasium hydroxide)
Soluble hydroxides of Group IA metals
Acid dissociation constant (Ka)
-equilibrium state
-weak acids
Ka= [H3O+] [A-]/ [HA]
The smaller the Ka the weaker the acid= the less it
will dissociate.
Base dissociation constant (Ka)
K b= [B+] [OH-]/ [BOH]
The smaller the Kb the weaker the base = the less it
will dissociate.
What is considered a weak acid
K a is less than 1.0
What is considered a weak base
K b is less than 1.0.
Kw=
Kw= [H3O+][OH-]= 10-14
Ka, acid x Kb, conj base = Kw= 10-14
Kb, base x Ka, conj acid = Kw= 10-14
Acetic acid
CH3COOH
Neutralization reaction
HA(aq) + BOH(aq)-----> BA(s) +
H2O (l)
NH3 is a weak/strong base
weak
Weak bases are often not
hydroxides
Calculating the unknown conc of the titrand through the equation:
Na Va= Nb Vb
Na: acid normality
Va: acid volume
Nb: base normality
Vb: base volume
Sodium acetate: salt of the weak acid acetatic acid
CH3COO-Na+
Amonium chloride: salt of the weak base ammonia
NH4 +Cl-
Carbonic acid
H2CO3
Henderson-Hasselbach equation is used to
estimate the pH or pOH of the buffer solution.
pH= pKa + log [A-]/[HA]
pOH= pKb + log [B+]/[BOH]