ELECTROPHILE
 
Any species, which accepts a pair of electrons, called electrophile
EXAMPLE: AlCl3, FeCl3, FeBr3
NUCLEOPHILE
 
Any species, which donates a pair of electron, is called Nucleophile
EXAMPLE: NH3, OH-
BASICITY
 
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:
HCl (aq) H+ + Cl- : Basicity = 1
H2SO4(aq) 2H+ + HSO4- : Basicity = 2
ACID
BASICITY

HCl, HNO3

CH3COOH

H2SO4

Oxalic acid

1

1

2

2
ACIDITY
 
Acidity of base is defined as the no of ionizable hydrogen ions (OH-) present in one molecule of a base is called acidity.
NaOH(aq) Na+ + OH- : Acidity = 1
Ca(OH)2(aq) Ca+2 + 2OH- : Acidity = 2

BASE

ACIDITY

NaOH

Ca(OH)2

KOH

1

2

1
PH SCALE
 
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.
DEFINITION
 
pH is defined as "the negative logarithm to the base 10 of the molar concentration of hydrogen ions (H+).
Formula :
pH = -log [H+]
POH
 
Meaning of pOH:
The symbol POH stands for "power of hydroxyl ion"
DEFINITION
 
pOH is defined as "the negative logarithm to the base 10 of molar concentration of hydroxyl ions (OH-).
Formula :
pOH = -log [OH-]
IMPORTANT POINTS:
1. Values of pH scale ranges from zero to fourteen.
pH scale: 0(strong acidic)_ _ _ _ _ _ _7(neutral)_ _ _ _ _ _ _14 (strong alkaline)

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.

5. The sum of pH & POH of a solution is equal to 14.

PH + POH = 14
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