1. Acid Base Reactions and Salts

2. Acid – Base Reactions
A reaction between an acid and a base is called neutralization. An acid-base mixture is not as acidic or basic as the individual starting solutions.

3. Equations With Acids
Acids undergo characteristic double replacement reactions with oxides, hydroxides, carbonates and bicarbonates.
e.g.
2HCl (aq) CuO (s)  CuCl2 (aq) H2O (l)
2HCl (aq) Ca(OH)2 (aq)  CaCl2 (aq) H2O (l)
2HCl (aq) CaCO3 (aq)  CaCl2 (aq) H2O (l) CO2 (g)
2HC l (aq) + Sr(HCO3)2 (aq)  SrCl2 (aq) + 2H2O (l) CO2 (g)

4. Equations With Acids
Bases undergo a double replacement reaction with acids called neutralization:
NaOH (aq) HCl (aq)  H2O (l) NaC l (aq)
In words this well known reaction is often described as:
“acid plus base = salt plus water”
We previously discussed this reaction when describing types of reactions.

5. Acidic Single Replacement Reactions
Another property of acids is their reaction with certain metals to produce hydrogen gas, H2 (g).
Zn (s) HC l (aq)  H2 (g) ZnCl2 (aq)
This is an example of a single replacement reaction and is a redox reaction.
Total ionic equation:
Zn (s) H+ (aq) Cl- (aq)  H2 (g) Zn2+ (aq) Cl- (aq)
Net ionic equation:
Zn (s) H+ (aq)  H2 (g) Zn2+ (aq)

6. Acid – Base reactions
Each salt listed in this table can be formed by the reaction between an acid and a base.

7. Salts
Salts are the ionic product of an acid base neutralization reaction.
Acidic Salts are formed from a strong acid and a weak base.
Neutral salts are formed from a strong acid and strong base.
Basic salts are formed from a strong base and a weak acid.
Give the acid and base the following salts were formed from and label the salts as acidic, basic, or neutral.
NaCl
NaC2H3O2
NH4Cl
HCl + NaOH
NaCl + HOH
neutral salt
s.a.
s.b.
HC2H3O2 + NaOH
NaC2H3O2 + HOH
basic salt
w.a.
s.b.
HCl +
NH4OH
NH4Cl
+ HOH
acidic salt
s.a.
w.b.

8. More on Salts

9. pH paper