Arrhenious Concept of Acid and Base

Statements

This concept is the oldest concept to explain about acid and base.According to Arrhenious concept,acid are those of substance which produce hydrogen ion (H+ions) in water.strong acid are those acid which completely ionized into its ions and produce high concentration of hydrogen ion.weak acid are those Acid which partially ionized into its ions in water and produced low concentration of H+ ions.

  • Example of strong acid, HCL, H2SO4, HNO3, H3PO4, etc.
  • Example of weak acid, H2CO3, HCOOH, CH3COOH, 2COOH, etc.

similarly, Acoording Arrhenious Concept, Base are substance which produce OH – ions in water. strong Basa are those substance, which completely ionized into its ions in water and produce high concentration of OH-ions. Weak base are those base which partially ionized into its ions in water and produce low concentration of OH-ions.

  • Example of strong base:NaOH,KOH,Mg(OH)2,etc.
  • Example of weak base:NH4OH,Fe(OH)2,Zn(OH)2,etc.

According to Arrhenious Concept, strength of acid and base can be explained on the basis of ionization constant of Acid(Ka)and ionization constant of base(‘Kb).Strong acid completely ionised into its ions. so ,posses higher value of Ka .While weak acid partially ionized into its ions and posses lower value of Ka.Similarly strong base are completely ionized into it ions nd possess higher value of Kb.while weak base partially ionized into its ions and posses lower value of ‘Kb‘.

Strength of acid and base can be expressed in terms of Pka, similar to pH. for acidin terms of PKb similar to POH for base. Acid having higher value of Pka are weaker acid than the acid having lower value of Pkb.similarly ,base having higher value of Pkb are weaker base than the base having low value of Pkb .

According to the Arrhenious concept combination of H+ions produced from a acid is OHions produced from base.where acid and base are completely lost their properties to from neutral substance, water is called Neutralization reaction.

Limitation of Arrhenious Concept

  • According to this concept properties of acid and base are explained only in solvent water that is this theory cannot explain acidic and basic properties without water.
  • Compounds like Sulphur Dioxide, carbon dioxide etc are acidic in nature.similaraly compounds likeNa2CO3,K2CO3 are basic in nature. this concept cannot explain acidic and basic properties of such compounds.

This concept is the oldest concept to explain about acid and base.According to Arrhenious concept,acid are those of substance which produce hydrogen ion (H+ions) in water.strong acid are those acid which completely ionized into its ions and produce high concentration of hydrogen ion.weak acid are those Acid which partially ionized into its ions in water and produced low concentration of H+ ions.

This concept is the oldest concept to explain about acid and base.According to Arrhenious concept,acid are those of substance which produce hydrogen ion (H+ions) in water.strong acid are those acid which completely ionized into its ions and produce high concentration of hydrogen ion.weak acid are those Acid which partially ionized into its ions in water and produced low concentration of H+ ions.

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