Strong and Weak Acids and Bases
The strength of any acid depends upon the extent to which it gives hydrogen
ions in solution. If the concentration of H+ ions in a solution is
high the acid is said to be strong.
e.g. HCl, H2SO4,
HNO3 etc.
If the concentration of H+ ions in a
solution is low the acid is said to be weak.
e.g. Oxalic, tartaric, H2CO3
etc.
Similarly, strong bases are those, which when dissolved in water, readily
give OH- ions.
e.g. NaOH, KOH
On the other hand, weak bases are those which when dissolved in water ionize
to a small extent (do not readily give OH- ions).
e.g. NH4OH, Mg(OH)2,
Ca (OH)2
Properties of Acids and Bases
PROPERTY ACIDS BASES
1) Physical Properties
a) Taste Sour Bitter
b) Conductivity Good conductor Soluble bases are
good conductor
c) Nature Corrosive Slippery to touch
2) Indicator Properties
Color change
a) Litmus Blue to Red Red to Blue
b) Methyl orange Orange to Pink Orange to Yellow
c) Phenolphthalein Colorless Colorless to Pink
3) Chemical Properties
a) Neutralizes bases to give salt Neutralizes acids to
& water give salt & water
NaOH + HCl� NaCl + H2O
HBr + KOH �
KBr + H2O
b) Reacts with carbonates Reacts with CO2 to
to liberate CO2 gas to form carbonates.
K2CO3+2HCL�2KCl
+ CO2 2NaOH + CO2
+ H2O
� Na2CO3
+ H2O
c) Liberates hydrogen Liberates ammonia
with active metals with ammonia salts
Zn + 2HCl � ZnCl2
+ H2
2NH4Cl + Ca(OH)2
�2CaCl2
+ 2H2O +
2NH3
Uses of Acids and Bases
| Acids |
Bases |
| Use |
Example |
Use |
Example |
| 1 Eye wash |
Boric acid |
1 Soaps |
NaOH |
| 2 Cooking |
Acetic acid |
2 Water
softening |
Ca (OH)2
|
| 3 Drinks |
Carbonic
acid |
3 Stain
remover |
NH4OH |
| 4 Ink stain
remover |
Oxalic acid |
4 Fire
extinguishers |
Al(OH)3
|
| 5 Food
preservation |
Boric acid |
5 As antacid |
Mg(OH)2
|
| 6 Baking |
Tartaric
acid |
6 Bleaching
powder |
Ca (OH)2
|
| 7 Tanning
industry |
Hydrochloric
acid |
7 Alkaline
batteries |
KOH |
| 8 Medicine |
Citric acid |
|
|
