acids and bases Flashcards
Acids dissociate in water to produce
H+ ions
Bases dissociate in water to produce
OH- ions
Bronsted – Lowery Acids lose ______ to
become conjugate bases of the original acid.
protons
* H+ ions fall off of the acid
Bronsted – Lowery Bases accept ______ to
become conjugate acids of the original base.
protons
* They pick up H+ ions
Problems with Arrhenius
1) Only true for bases that contain Hydroxide
Ions, OH-
. * There are bases that do not have OH- ions, but
still make solutions basic.
2) Only true for reactions that take place in
aqueous solutions.
The “Big Six” Strong Acids
HClO4 (aq) HCl (aq)
HI (aq) HNO3 (aq)
HBr (aq) H2SO4 (aq)
Strong Bases
Li Na K Ca Sr Ba
Weak Bases Containing Nitrogen
The lone pair on the nitrogen accepts protons in
solution.
Strong acids always have very ______
conjugate bases
weak
HCl is a strong acid because Cl-(aq) is a weak
base.
Cl- cannot hold onto H+ in water.
Very weak acids always have very _______
conjugate bases
strong
Acid strength increases when moving
down a group
Conjugate base strength ______ when
moving down a group
down a group
two types of Oxoacids
There are two types of Oxoacids
1) An OH group bonded to an element that is not
bound to other Oxygens (HOY acids)
H – O – Y
2) An OH group bonded to an element that is
bound to other Oxygens (HYOn acids)
O
|
H – O – Y – O
HOY Oxoacids Acid strength increases as the electronegativity
of Y increases
Electrons are pulled out of O-H bond
* Makes the Oxygen a little bit positive
* This weakens the bond between O and H
* H+ breaks off easily
HYOn Oxoacids Acid strength increases as
more Oxygens are added to the central Y
Oxygen is a very electronegative element.
As you add more oxygen atoms to the
Y, the electronegativity at that end of the
compound increases. This makes it easier for the H+ion to fall
off.
Carboxylic acids are
weak organic acids
O || R – C – O – H
pH
Expresses the negative power of 10
for the concentration of H+
(formula) pH = ?
pH= -log10 [H+]
When dealing with binary acids within halogens (H-X, eg. HF, HCl, HBr), how do we determine its acid strength?
Bond strength - The strength of the H-X bond determines how easily 𝐻+ is released.
As you move down the periodic table, atomic size increases, making the H-X bond weaker and easier to break.
Acid Strength Trend (strongest to weakest):
𝐻𝐼>𝐻𝐵𝑟>𝐻𝐶𝑙>𝐻𝐹
Ka
[PRODUCT]/[REACTANT]
What are the Ka values of very strong acids? (big six)
Very large Ka values
What type of acids are e –COOH or –CO2Hat the end of the formula for a compound?
weak organic acid (carboxylic
acid)
The strong the acid, the ____ the pKA
smaller,
pKw formula (pH)
pKw= pH + pOH = 14
