2. Ions
Some times substances go through a
reaction that breaks off a hydrogen or
even a hydrogen and an Oxygen.
These extra Ions (Charged Particles) are
what make up Acids and Bases.
H2O -> H+ + OH-
3. Ions
Because the Single Hydrogen no longer
shares that electron is becomes positively
charged.
He is now called a Hydrogen Ion.
4. Ions
The Oxygen and Hydrogen now have an
extra electron and become negatively
charged.
They are now called a Hydroxide Ion.
5. Acid
Any substance that has extra Hydrogen
Ions is an acid.
The more Hydrogen Ions the more acidic.
6. Basis
When a substance has extra hydroxide
ions (OH- ) then it is a base.
The more hydroxide ions the more basic.
(Bases can also be called Alkaline)
7. pH Scale
The pH scale was created to better
compare the relative concentration of
Hydrogen ions.
pH stands for partial Hydrogen.
The scale ranges from 0 to 14 and each
step is a multiple of 10. The scale is
logarithmic.
8.
9. pH
Example:
Urine generally has a pH of 6 where as
water has a pH of 7.
This means that Urine has 10 times more
Hydrogen Ions than water.
10. pH
A pH of 7 is considered neutral.
This means that there as many Hydrogen
ions as there are hydroxide ions.
They balance each other out.
11. Topic 10: ACIDS, BASES &
SALTS 11
T E R M S
ACIDS are substances that form hydrogen ions (H+
(aq))
when dissolved in water eg
BASES are hydroxides that react and neutralize.
In acid solutions there are more H+ ions than
OH- ions.
In alkaline solution there are more OH- ions
than H+ ions.
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12. Topic 10: ACIDS, BASES &
SALTS 12
Strong or Weak
- Acids or Bases that dissociate completely are Strong
Acids/Bases.
Acids or Bases that dissociate only partially are Weak
Acids/Bases
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13. Topic 10: ACIDS, BASES &
SALTS 13
Physical Properties of Acids & Bases
ACIDS
Acids taste sour (e.g. vinegar, lemon juice).
Acids are harmful to living cells.
Aqueous solutions of all acids contain hydrogen ions.
Acid turns blue litmus red.
Strong acids are corrosive.
BASES
Alkalis are taste bitter
Strong alkalis are corrosive.
Aqueous solutions of all alkalis contain hydroxide ion.
Alkalis turns red litmus blue.
Soapy touch.
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15. Topic 10: ACIDS, BASES &
SALTS 15
SALTS
When H+ ion of an acid is replaced by a metal ion, a
salt is produced e.g.
H2SO4+ 2NaOH====== Na2SO + 2H2O
Here sodium sulphate (Na2SO4) is the salt formed.
Salts are ionic compounds.
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16. Topic 10: ACIDS, BASES &
SALTS 16
Methods of making Soluble
Salts
1) ACID + METAL SALT + HYDROGEN
2) ACID + BASE SALT + WATER
3) ACID + CARBONATE SALT + WATER +
CARBON DIOXIDE
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17. Topic 10: ACIDS, BASES &
SALTS 17
Types of Salts
Normal Salts:
Normal salts are formed when all the
replaceable hydrogen ions in the acid have
been completely replaced by metallic ions.
HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)
H2SO4(aq) + ZnO(aq) ZnSO4(aq) + H2O(l)
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18. Types of Salts
Acid salts:
Acid salts are formed when replaceable
hydrogen ions in acids are only partially
replaced by a metal.
H2SO4 + KOH KHSO4 + H2O
H3PO4 + NaOH NaH2PO4 + H2O
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Topic 10: ACIDS, BASES &
SALTS 18
19. Types of Salts
Basic Salts:
Basic salts contain the hydroxide ion, OH-.
They are formed when there is insufficient
supply of acid for the complete neutralization of
the base.
Zn(OH)2 + HCl Zn(OH)Cl + H2O
Mg(OH)2 + HNO3 Mg(OH)NO3 + H2O
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Topic 10: ACIDS, BASES &
SALTS 19
20. Topic 10: ACIDS, BASES &
SALTS 20
USES OF SALTS
S.No
.
SALT USE
1 Ammonium Chloride In torch batteries
2 Ammonium Nitrate In fertilizers
3 Calcium Chloride As drying agent
4 Iron Sulphate In Iron tablets
5 Magnesium Sulphate In medicine
6 Potassium Nitrate In gunpowder etc.
7 Silver Bromide In photography
8 Sodium Chloride Making NaOH
9 Sodium Stearate In making soap.
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