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ARRHENIUS ACID-BASE CONCEPT

CHARACTERS OF ACIDS:
(1) acids convert blue litmus to red and methyl orange  indicator to  red .
(2) Sour in taste.
(3) It liberate hydrogen gas with active metals.
(4) Acids neutralised the effect of base 
(5) acids increases the conduction of water.
CHARACTERS OF BASES:
(1) bases convert the red litmus to blue and methyl orange indicator to yellow.
(2) Phenylphthlene indicator (white) to pink.
(3) Bitter in taste and soapy in touch.
(4) Bases neutralised the effect of acid.
(5) They increases conductance of water.
ACID BASE CONCEPT:
(1) ARRHENIUS ACID-BASE CONCEPT
(2) BRONSTED LOWERY ACID-BASE CONCEPT 

(3) LEWIS ACID-BASE CONCEPT

(1) ARRHENIUS ACID-BASE CONCEPT
the substance which produces H+ in aqueous solution is consider as acid and the substance which give produces OH- in aqueous solution is consider as base
Arrhenius theory depend upon dissociation of water.







Type of Arrhenius acids:

Type of Arrhenius Bases :
         

Feature of Arrhenius theory:

(1) OH¯ ion is present also in hydrated form of H3O2¯, H7O4¯, H5O3¯
      H+ ion is present also in hydrated form of H3O+, H5O2+, H7O3+, H9O4+
(2) Neutralisation reaction can be easily explain by the Arrhenius theory .acids furnishing H+ ion  in water to large extent are strong acid.

Strength of acid or base:

(3) If Ka increases then concentration of H+ increases hence acidic strength is increases.
Similarly the base furnishing OH- ions to the large extent are strong base
Kb is dissociation constant for bases, if Kb is increases OH- increases, hence basic strength of base

(4)The term strong is used only for those acids or bases or bases which dissolved almost completely in water.

LIMITATIONS OF ARRHENIUS THEORY
(1) This theory explain nature of a substance only aqueous medium . It cannot be applied for non aqueous solution.
(2) It could not explain formation of hydronium ions like H3O- , H5O2- , and H7O3- .
(3) the nature of aqueous solution of AlCl3, CuSO4 ,BF3, B(OH)3 etc are acidic and aqueous solution of NH3 ,NaCO3 ,RNH2 R2NH,  R3N , C2H5N  etc are basic in nature cannot be explain by Arrhenius Concept.
(4) there are many  Amphoteric hydroxide Zn(OH)2  Al(OH)3 ,Pb(OH)2 , which cannot be  explain  by Arrhenius Concept.
(5) Arrhenius explain only when H+ is released it cannot explain when H+ is taken.
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