Transcript Acid-Base Reactions

Acid-Base Reactions
 Strong
and Weak Acids
 Titration
 Common Acid Names
Textbook section 4.3
What is an ACID?

Defined:


ACID Produces
H+ ions in water
solution
BASE Produces
OH- ions in
water solution
Acid Characteristics:
–Sour Taste (lemon)
–Change Indicators Colors (litmus blue to red)
Strong Acids Ionize
completely.
HCl (aq)  H+ (aq) + Cl- (aq)
 The strong ACIDS are:
1.
HCl
2.
HBr
3.
HI
4.
HNO3
5.
H2SO4
6.
HClO4

Strong Acids
What are the names of
these acids?
Check the partner of the
“H” for a hint.
These must be memorized.
Weak Acids
Weak acids ionize partially.
General formula:
HB
H+
+ B
Double arrow means reversible or it
does not go to completion.
The equilibrium includes both
products AND reactants.
Compare # of HCl ions in solution to HF ions in solution. Each w/ 1.0 M concentration.
Strong Bases
Strong Bases Ionize
Completely
 NaOH  Na+ + OH Hydroxides are
commonly strong bases.
Including:
LiOH
KOH
Ca(OH)2
Sr(OH)2
Ba(OH)2

Weak Bases
Produce OH- ions by reacting with the
water.
NH3 aq + H2O aq   NH4+ aq + OH- aq
Pulling an H+, and leaving OH- behind.
We often write water HOH, to easily
keep track of this water reaction
Include: ammonia NH3
amides R-NH2
Weak bases are weak electrolytes. The bulb
will light up but it will be dim
Acid-Base Reactions


Mix and acid and base
what happens?
The results depend
upon the strength of
the reactants.



3 TYPES:
1 Strong ACID - Strong BASE
2 Weak ACID – Strong BASE
3 Strong ACID – Weak BASE
Strong ACID + Strong BASE
Neutralization Reaction occurs
 The products are water, and an
aqueous salt. (ions)
Consider Nitric Acid and Sodium
Hydroxide
H+ + NO3- + Na+ + OH- 
Since they are “strong”, they fully
Neutralization produces
ionize

Water and a salt.
Animation of Nitric acid and Sodium Hydroxide
Weak Acid – Strong Base


Write the complete
equation for this
reaction
Identify any spectator
ions and then write a
net ionic equation.
2 step reaction occurs,
The acid HF partially
dissociates to H+ + F
Then the Base NaOH,
which has dissociated to
produce OH- ions (plus
the Na+ ions)
The H+ and OH- combine
to from water
Strong ACID – Weak BASE
The weak base gets “protonated”
The strong acid is already dissociated into H+ and
B-.
Consider ammonia and Hydrochloric Acid
NH3 + H+ + Cl-  NH4+ + ClMethylamine and Nitric Acid
CH3NH2 + H+ 
CH3NH3+

Poem That Makes Sense After Studying
Predicting Reactions:
Johnny finding life a bore, drank some H2SO4.
Johnny's father, an M.D., gave him CaCO3.
Johnny's neutralized, it's true,
But now he's full of CO2.
Acid Base Titration
An standardized acid (known concentration)
may be used to determine the
unknown strength of a base. (or visaversa)
Using an indicator (solution that changes color)
you can know when the added solution is
exactly equal to the unknown.
this is known as the EQUILVALENCE
POINT.
Acid-Base titration
Objective: Determine the equivalence point.
Equivalence point nOH- = nH+
If 25.00mL of 0.0800M NaOH is needed to react with
10.00 mL of HCl. What is the molarity of HCl?
1.
2.
Write the reaction
Use M1V1=M2V2
In this case the formula could be written MOH- VOH- = MH+VH+
Acid Definitions: Arrhenius
Bronsted-Lowry
Arrhenius:
Acids put H+ into water
water
Bronsted-Lowry Acids:
Bases put OH- into
“ADP”
Acids donate protons
Bases accept protons