Different definitions of acids and bases. Acids are proton donors (. Brønsted. Lowry definition). they generate H. 3. O. +. in water (Arrhenius definition). Bases are proton acceptors. they generate OH. ID: 532818
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Conjugate acids and bases
Slide2Different definitions of acids and bases
Acids are proton donors (
Brønsted
Lowry definition)
they generate H
3
O
+
in water (Arrhenius definition)
Bases are proton acceptors
they generate OH
-
in water
which is an acid/base?
HF +
H
2
O
H
3
O
+
+ F
-
NaHCO
3
+
H
2
O
Na
+
+H
2
O + CO
2
+ OH
-
Slide3Follow the proton
HF + H2O H3O+ + F-NaHCO3 + H2O Na++ H2O+CO2 +OH-Joining equilibrium to acid base…What about the reverse reaction?
H
+
H+
H
+
H
+
Slide4Conjugate acids and bases
When you run the reverse reaction you find the products are also acids and bases. The acids and bases that are formed are called
conjugate acids or bases
H
2
O
+
HF
H
3
O
+
+
F
-
base
acid
conjugate acid
conjugate base
NaHCO
3
+
H
2
O
Na
+
+H
2
O + CO
2
+
OH
-
base
acid
CA
CB
Slide5Label Acid, Base, Conjugate Acid, Conjugate Base
HClO
3
+
H
2
O
ClO
3
-
+
H
3
O
+
A B CB CA
ClO
-
+
H
2
O
HClO
+
OH
-
B A CA CB
HSO
4
-
+ H
2
O
SO
4
2-
+
H
3
O
+
A B CB CA
LiOH
+ H
2
O
Li
+
+ H
2
O
+
OH
-
B A CA CB
Slide6Conjugate acids and bases …
Conjugate acids and bases determine if an acid or base is strong or weak.
If the conjugate acid/base readily reacts to run the reverse reaction it is a
weak
acid/base.
If it does
not
react in the reverse reaction the acid or base is
strong.
Slide7Strong acids
Acid
formula
Nitric Acid
HNO
3
Sulfuric Acid
H
2
SO
4
Hydrochloric acid
HCl
Slide8Strong Bases
NameFormulaNameFormulaSodium HydroxideNaOHCalcium HydroxideCa(OH)2Potassium HydroxideKOHStrontium HydroxideSr(OH)2Barium HydroxideBa(OH)2
these make a lightning bolt
on the periodic table!
Slide9More with conjugate acids/bases
H
2
SO
4
+ H
2
O
H
3
O
+
+ HSO
4
-
Sulfuric acid is a
strong
acid so its conjugate
base
, HSO
4
-
, will
not
run the reverse reaction.
HSO
4
-
is actually an acid in water.
HSO
4
-
+ H
2
O
H
3
O
+
+ SO
4
2-
SO
4
2-
will run the reverse reaction, so it is a
weak
acid
Slide10Other weak acids and bases
Weak Acids
Acetic Acid (vinegar)
Citric Acid
Ascorbic Acid (vitamin C)
Boric Acid
Carbonic Acid
Weak Bases
Sodium Bicarbonate
Ammonia
Sodium Hypochlorite (bleach)
Slide11Danger!!!
Strong and Weak acids and bases do NOT necessarily tell you how dangerous they are.
Concentration is the most important factor for determining danger.
Ammonia is a weak base, if it is highly concentrated it can burn you.
Dilute hydrochloric acid (less than 1 M) is not particularly dangerous
Slide12What is water
Water is either an acid or base depending on the situation.
Anything that is either an acid or a base is called
amphoteric
.
Several things are amphoteric, like parts of you.
Slide13Donating Protons
Hydrochloric acid (HCl) can donate 1 proton, so it is called a
monoprotic acid
.
Sulfuric acid (H
2
SO
4
) can donate 2 protons, so it is called a
diprotic acid
.
Phosphoric acid (H
3
PO
4
) can donate 3 protons, so it is called a
triprotic acid
.
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