Acids and Bases: Salts
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Introduction
Molecular Structure
Ionization Constants
Salts
Buffers
Lewis Theory

Salts of Strong Acids and Strong Bases

When nitric acid is combined with potassium hydroxide potassium nitrate is formed:

HNO3 + KOH KNO3 + H2O

Complete the following statements:

1

 K+ is the of KOH
   and will cause the pH of the solution to

2

 NO3- is the of HNO3
   and will cause the pH of the solution to

3

The pH of a KNO3 solution will be

K+ is the conjugate acid of the strong base KOH.

NO3- is the conjugate base of the strong acid HNO3.

A very weak acid or base will not affect the pH of an aqueous solution.

If neither ion of the salt causes the pH to increase or decrease, the solution will be neutral.

Good! A salt formed from the reaction of a strong acid and strong base will act neither as an acid nor base.

Salts of Strong Bases and Weak Acids

When formic acid reacts with potassium hydroxide, sodium formate is formed:

HCO2H + KOH KHCO2 + H2O

You have already determined that K+ is the very weak conjugate acid of KOH and will not affect the pH of a solution. What about HCO2-?

Complete the following statements:

1

 HCO2- is the of HCO2H
   and will cause the pH of the solution to

2

The pH of a KHCO2 solution will be

HCO2- is the conjugate base of the weak acid HCO2H.

How will a weak base affect the pH of a solution?

If the cation does not affect the pH and the anion causes the pH to increase, will the resulting solution be acidic or basic?

Good! A salt formed from the reaction of a weak acid and strong base will act as a base, causing the pH of a solution to increase.

Salts of Strong Acids and Weak Bases

When nitric acid reacts with ammonia, ammonium nitrate is produced:

HNO3 + NH3 NH4NO3

You have already determined that NO3- is the very weak conjugate base of HNO3 and will not affect the pH of the solution. What about NH4+?

Complete the following statements:

1

 NH4+ is the of NH3
   and will cause the pH of the solution to

2

The pH of a NH4NO3 solution will be

NH4+ is the conjugate acid of the weak base NH3.

How will a weak acid affect the pH of a solution?

If the cation causes the pH to decrease and the anion does not affect the pH, will the resulting solution be acidic or basic?

Good! A salt formed from the reaction of a strong acid and weak base will act as an acid, causing the pH of a solution to decrease.

Salts