11 Acids and Bases Flashcards
Arrhenius Definition of acid
An acid is a substance that
ionizes in water and produces hydrogen ions (H+ ions)
Arrhenius definition of Bases
A base is a substance that
ionizes in water and produces hydroxide ions (OH- ions)
Bronsted-Lowry definition of an acid
An acid is a substance that is capable
of donating a proton, which is the same as donating an H+ ion.
Bronsted-Lowry definition of Base
A base is a substance that is capable of
accepting a proton.
Lewis definition of an acid
An acid is an electron pair
acceptor.
Lewis definition of a base
A base is an electron pair
donor.
p(anything) = -log(anything)
pH =
pOH =
pKa =
pKb =
- log(H+)
- log(OH-)
- log Ka
- log Kb
In a solution
When [H+] = [OH-],
the solution is neutral, and pH = 7
In a solution when [H+] is greater than [OH-],
the solution is acidic, and the pH is less than 7
In a solution when [H+] is less than [OH-],
the solution is basic, and the pH is greater than 7.
Acid Dissociation Constant
Ka =
([H+][A-]) / [HA]
[H+] = molar concentration of hydrogemn ions (M)
[A-] = molar concentration of conjugate base ions (M)
[HA] = molar concentration of undissociated acid molecules (M)
Base Dissociation Constant
Kb =
([HA+][OH-]) / [B]
[HA+] = protonated base ions (M)
[OH-] = molar concentration of hydroxide ions (M)
[B] = unprotonated base molecules (M)
Important Strong Acids
HCl, HBr, HI, HNO3, HClO4, H2SO4
Important Strong Bases
LiOH, NaOH, KOH, Ba(OH)2, Sr(OH)2
If a salt is composed of the conjugates of a strong base and a strong acid
its solution will be neutral.
If a salt is composed of the conjugates of a weak base and a strong acid,
its solution will be acidic.
If a salt is composed of the conjugates of a strong base and a weak acid
its solution will be basic
If a salt is composed of the conjugates of a weak base and a weak acid,
the pH of its solution will depend on the relative strengths of the conjugate acid and base of the specifics ions in the salt.
The Henderson-Hasselbalch Equation
pH =
pKa + log([A-] / [HA])
[HA] = molar concentration of undissociated weak acid (M)
[A-] = molar concentration of conjugate base (M)
pOH = pKb + log([HB+] / [B]
[B] = molar concentration of weak base (M)
[HB+] = molar concentration of conjugate acid (M)
Polyprotic Acids
Acids that can give up more then one hydrogen.
Amphoteric substances
substances that can act as either an acid or a base.
An Acid Anhydride is
a substance that combines with water to form an acid.
A basic Anhydride is
a substance that combines with water to form a base.
Neutralization reaction
Acid + Base = Water + Salt
In a good buffer solution
pH =
pKa
and
pOH = pKb
pKa + pKb =
14
kakb =
1 X 10-14
pH + pOH =
14
The equivalence point is
the point in titration when exactly enough base has been added to neutralize all the acid that was initially present.
When a strong acid is added to a weak base(or vice versa), before reaching the equivalence point, the reaction goes through a buffer region.
At the point when exactly half of the acid is converted into the conjugate base, is the
half equivalence point. At this point pH = pKa
Examples of Lewis Acids
All
Cations are Lewis acids since they are able to except electrons
An atom, ion, or molecule with an incomplete octet of electrons can act as an lewis acid.
Molecules where the central atom can have more than 8 valence shell electrons can be electron acceptors, and thus are classified as lewis acids.
Molecules that have multiple bonds between two atoms of different electronegativities.
An atom, ion, or molecule with a lone-pair of electrons can be a
lewis base.
An electrolyte is any substance containing free ions that
make the substance electrically conductive.
