15.3 Acid-Base Reactions.pptx

 The seven most common strong acids:

 HCl hydrochloric acid  HBr hydrobromic acid

 HI hydroiodic acid

 HNO₃ nitric acid  HClO₃ chloric acid

 HClO₄ perchloric acid  H₂SO₄ sulfuric acid

Bronsted-Lowry Acids & Bases

Bronsted-Lowry Acids & Bases

 Examples of common weak acids:

acetic acid, citric acid,

phosphoric acid

 Examples of substances with negligible acidity:

CH₄ H₂ OH –

Acid – Base Reactions

 A reaction between

an acid and a base is called neutralization. An acid-base

mixture is not as

Conjugate acid base pairs

 A conjugate base is a base that is

produced when an acid gives up a proton. H₂SO₄ → HSO₄- + H+

 In this case the HSO

4- is the base

produced when the H₂SO₄ gave up the H+

 The only difference between a conjugate

acid/base pair is one little hydrogen ion.

 The acid has it and the base does not.

 So to determine the conjugate base all

you do is subtract one H from the acid and make the resulting ion (-)

Do some practice problems

Learning Check!

Label the acid, base, conjugate acid, and conjugate base in each reaction:

HONORS ONLY!

HONORS ONLY!

HCl + OH

   Cl

+ H

O

HCl + OH



  Cl

+ H

2

O

H

O + H

SO

   HSO

+ H

3

O

H

O + H

SO



  HSO

+ H

Bronsted-Lowry Acids & Bases

 An inverse relationship exists between the

strength of an acid and its conjugate base or between a base and its conjugate acid.

Strong acids form very weak conjugate

bases (usually have negligible basicity).

Weak acids form stronger (but still fairly

weak) conjugate bases

Substances with negligible acidity form

Bronsted-Lowry Acids and

Bases

The stronger the acid, the weaker the conjugate

base

The stronger the base,

Example: Use Fig. 15.6 to predict whether the

equilibrium lies predominantly to the left or to the right:

Bronsted-Lowry Acids & Bases

HSO₄- (aq) + CO₃2- (aq) _SO

42- (aq) + HCO3- (aq)

acid base Conj.

Acid-Base Behavior

• Consider a compound having the formula HOX.

• If X is highly electronegative, it will have a

strong attraction for the electrons shared with O.

– The O, will in turn, pull strongly on the electrons held

shared with H.

– _{This H will then be easily lost = acid}

• If X has a low electronegativity, the oxygen will

pull the electrons away from X.

– The hydrogen will remain joined to the oxygen.

– _{Since the O and H can easily remain together, it is}

likely that OH- will be formed = base

• Nonmetals tend to have high EN = acids

Neutralization

In general: Acid + Base  Salt + Water

All neutralization reactions are double displacement reactions.

HCl + NaOH  NaCl + HOH

HCl + Mg(OH)₂ 

Neutralization Reaction of

Weak Acid

HC₂H₃O₂(aq) + NaOH(aq)  NaC₂H₃O₂(aq) + H₂O(l)

Weak acid strong base soluble salt water

HC₂H₃O₂ + Na+ + OH-  Na+ + C

2H3O2- +

H₂O(l)

HC

H

O

(aq) + OH

(aq)



C

H

O

(aq)+

H

O(

l

)

*Remember, only strong electrolytes are written as ions.*

2HCl (aq) + Na₂S(aq)  H₂S(g) + 2NaCl(aq)

Hydrochloric acid + Sodium Sulfide 

2H+ (aq) + S2-(aq)  H

2S(g)

HCl (aq) + NaHCO₃(aq)  NaCl(aq) + H₂CO₃(aq)

H₂CO₃(aq)  H₂O(l) + CO₂(g)

HCl (aq) + NaHCO₃(aq)  NaCl(aq) + H₂O(l) + CO₂(g)

Hydrochloric acid + Sodium Hydrogen Carbonate 

H+ (aq) + HCO

Acids & Bases

For the following identify the acid and the base as strong or weak .

a. Al(OH)₃ + HCl 

b. Ba(OH)₂ + HC₂H₃O₂ 

c. KOH + H₂SO₄ 

d. NH₃ + H₂O 

Weak base Strong acid

Weak acid

Strong acid

Strong base

Strong base

Acids & Bases

For the following predict the product. To check your answer left click on the mouse. Draw a mechanism detailing the proton movement.

a. Al(OH)₃ + HCl 

b. Ba(OH)₂ + HC₂H₃O₂ 

c. KOH + H₂SO₄ 

d. NH₃ + H₂O 

AlCl

+ 3 H

O

Ba(C₂H₃O₂)₂ + 2 H₂O

K

SO

+ 2 H

O

NH

+ OH

-2

Acid – Base reactions

 Each salt listed in this

Amphiprotic vs amphoteric



Salts

can act as acids and

bases by donating or accepting

H

- usually H

3

O+ or OH

ions are



acid base



HCl + H

2

O



H

O

+ Cl

- Water is behaving as a base donates proton



base acid



O

+ H

2

O



OH

Acid Rain

What is Acid Rain?

SO₂ and NO₂/NO₃ from industry and cars Produce

H₂SO₄ and HNO₃ when combined with

water

Can fall as rain, snow and as solid

What are the effects?

 Forrest

depletion: tree death

 Can be seen in

NH in White Mountains

Clear lakes due to acid rain: clear

because

 Statues like this

one, show

corrosion due to acid rain.

 Copper and

Effects of Acid Rain

 Maple sugar

production in the Northeast may be

down due to acid rain: this is projected to

continue

 Car paints have had

to be reformulated and there are many products on the