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ELECTROPHILE
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| Any species, which accepts a pair of electrons, called electrophile | |||
| EXAMPLE: AlCl3, FeCl3, FeBr3 | |||
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NUCLEOPHILE
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| Any species, which donates a pair of electron, is called Nucleophile | |||
| EXAMPLE: NH3, OH- | |||
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BASICITY
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| Basicity
of acid is defined as the no of ionizable hydrogen (H+) ions
present in one molecule of an acid is called basicity. For example: |
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HCl
(aq)
H+ + Cl- : Basicity = 1H2SO4(aq)
2H+ + HSO4- : Basicity = 2 |
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ACID
|
BASICITY
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HCl, HNO3 CH3COOH H2SO4 Oxalic acid |
1
1 2 2 |
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ACIDITY
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| Acidity of base is defined as the no of ionizable hydrogen ions (OH-) present in one molecule of a base is called acidity. | |||
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NaOH(aq)
Na+ + OH- : Acidity = 1Ca(OH)2(aq)
Ca+2 + 2OH- : Acidity = 2 |
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BASE |
ACIDITY
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NaOH Ca(OH)2 KOH |
1
2 1 |
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PH
SCALE
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Meaning of pH: The symbol pH stands for "power of hydrogen ion" .pH scale is used to describe the acidic or basic nature of a solution. |
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DEFINITION
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| pH is defined as "the negative logarithm to the base 10 of the molar concentration of hydrogen ions (H+). | |||
| Formula : | |||
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pH
= -log [H+]
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POH
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| Meaning
of pOH: The symbol POH stands for "power of hydroxyl ion" |
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DEFINITION
|
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| pOH is defined as "the negative logarithm to the base 10 of molar concentration of hydroxyl ions (OH-). | |||
| Formula : | |||
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pOH
= -log [OH-]
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| IMPORTANT POINTS: | |||
| 1. Values of pH scale ranges from zero to fourteen. | |||
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pH scale: 0(strong acidic)_ _ _ _ _ _ _7(neutral)_
_ _ _ _ _ _14 (strong alkaline)
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2. If pH of a solution is less than ‘7’ then it is acidic. 3. If pH of a solution is greater than ‘7’ then it is alkaline. 4. If pH is ‘7’ then the solution is neutral. |
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5. The sum of pH & POH of a solution is equal to 14. |
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PH
+ POH = 14
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