Acid And Base

Posted by Anjum Shekh at May 1, 2021


The Term Acid derived from word acid means sour test acid have following features.

  • They term sour test
  • They term blue litmus to red
  • They React with base to from salt H2o

Ex: – HCL+NaOH H2o+Nacl

They Reaction with active mattle to involve Hydrogen gas

2Na+2Hcl 2Nacl+H2


The term base is derived form the word Alkali means ash of plant The following Nature of Base are as follows.

  • They have Bitter Test
  • They have shops Test
  • They term red litmus to blue
  • They React with acid to from solt and Water

Acid Base Concept

1. Arrhenius Acid Base concept:-

Accordingto this concept acid are those chemical species which have a tendency to Realize H+ions or OH ions in Water.

Bases are which have a tendency to Realize or give OH ions or Hydroxyl ions in the water.



This concept also neutralization and heat and neutralization by combination of acid and base.

HNo3 + KOH KNo3+H2o H=-13.7 Kcal

The Heat of neutralization is the heat of from of water molecule.

Utility or profit:-

1. This concept of Explain Acidic of not metallic Acid because they give H+ ions.

So3+H20 H2So4 2H++So4-2

2. This concept Explain the Basis Nature of Mattle ions oxide because they gave OH

Cao+H2O Ca (OH) 2 2OH+Ca+2


1. This concept is only is only explain in the water molecule.

2. There is no more escape

3. This concept is failed to explain to Acidic and Basic Nature of Substance in not protanic solvent.

2. Bransted-Lowry Acid Base Concept:-

In the order Rectifies draw backs of Arrhenius Acid Base concept Bronsted Lowery proposed an other Acid Base concept is Better Know as Bronsted Lowry Acid Base concept state that.

“Acid is an any species which have a tendency to Realize H+

and base is any species which have tendency to accept H+ from any solution when an acid realize H then Ramming part contain negative charge conjugate base .

These conjugate bases have a tendency to accept H+ ion.

Acid H+ +conjugate base


If any base reaction they are two type acid and base are reburied such acid base reaction is known as conjugate acid base reaction.

Ex.: – acid +base base+acid


H2So4+H2O H3+O+HSo4

Advantage of Lowry acid base concept:-

1. This concept required to particular type of ion or solution.

2. This concept also explains the hydrolysis of salt solution.

3. According to this concept all the protanic solvent and proton transfer reaction have been considered to be acid base reaction.

There are many acid which do not content H there molecule composition.

Ex.:- Fecl3, Alcl3, SNcl4

There area numbers of acid base reaction in which no proton transfer take place.

Ex.:- SO4 +So2 ⇆ so+2 so3

N2O4+N2O 2No+ +2NO3

3. Levis Acid Base concept:-

In order to rectify the draw back of bronsted Lowry acid base concept Levis proposed an other acid base concept which state that.

“Acid and species which have tendency to accept a pair of electron from the source.”

Because the central atom of acid has in complete octet there are also as electophil.

“BASE an species which have a tendency donate one or more than one lone pair of electron to the acid.”

Base are contain to or more extra electron from there octed they are called nucleophile.

In other word we can say that.

Lone pair donor……..base

Lone pair accepter………acid

On the basis of nature of species Levis Acid are classified are as.

  • Molecule was central atom has incomplete octed at as Levis Acid. ex.. [H3N BF3]

H3N: BF3

Levis base Levis acid

  • cation which accept one or more lone, pair of electron form co ordinate Bond with donating center of system (legend) at as acid Ag++ + 2CN

[NC Ag CN]


Advantage Levis acid Base concept:-

  • This concept does not depend upon the presence of a particular ions or element solvent.
  • These concepts include those reaction Which No protons (H+) take place.
  • This concept applicable many chemical Reaction occur in gases medium or at high temperature.


  • This concept does not explain the of acid and base
  • According to this concept, acid Base Reaction Should is a rapid but there are a many Reaction which occur at a slower rate.

4. Lux Flood Acid Base concept:-

In 1939 lux proposed an other acid Base concept which is modified by flood in 1947.

They proposed the acid base concept on the basic of the Oxide ions.

Base A base is any species which have a tendency to give up oxide ions o”

Acid A acid is an species which have a tendency to accept oxide ion an the other word we can say that.”

Oxide ion donor…….. Base

Oxide ion Accepter…… Acid

Ex. Co2 + Ca o CaCo3 salt

Acid base

Pbo+So3 PbSo4

According to concept amphoteric Substance are those which have a tendency gain and loss an oxide ion.

Ex.. Zno Zn+2+ O2

Al2O3 O-2 2Al O

Advantage Lux flood Acid Base Concept:-

This concept is useful in explaining the reactions which take place at a high temperature.


This concept has a limitation scope because Oxide only.

Solvent System Concept:-

This concept was proposed by frankly and modify kid din this concept Applicable in a both protanic and nonprotanic.

According to this concept

“As an Acid is any species which gives cationic (+) properties of the solvent.”

“As Base is a solute which gives Anionic (-) properties of solvent.”


NH3+NH3 NH+4+NH2

In non-protanic

SO2+SO2 SO3-2+SO+2

N2O4+N2O4 2NO++2NO3


Substance which furnished H3O+ in water NH4+ Ammonia are acid while those Substance which gives OH in water NH2 in ammonia are known as base.

NH4+Cl NH4++Cl


Like acid base Arrhenius acid base concept reutilisation reaction may can carried out in non protanic solvent.

ex. NH4Cl+NaNH2 2NH3+Nacl

Nacl+NaNO3 Nacl+2No2


  • Reutilization Reaction only occurs in the presence of solvent.
  • This concept gives only chemical properties acid base but physical properties were ignore.
  • It limits acid base phenomena to solvent system only.

Factor affecting the straight of Acid and Base:-

Effecting of Solvent:-

The strength of an acid depend upon the substance which acid as Base.

The capacity of acid to ionise is depend upon the strength of base of the solvent which acts as a Base.

The order of relative strength may be different in a different solvent.


Straric effect:-

Tersery Amine is less than secondary amine due to straric effect.

It is evident that the electron realising nature of amine group.

In tersery amine is more than that of secondary Amine but approach of the electron accepter H toward the nitrogen atom is difficult due to straric repletion of alky group.

In this condition three degree Amine is less Basic an nature.

Charge on species:-

The Acidic strength in increasing with increasing in position Charge and basic string increases in with negative charge.

Ex. Al+<Al++ <Al+++ acid

O<O basic


In halogen the acidic nature is increases with in the elect negativity of halogen atom the order of acid straight become in a following manner.


Acidic nature

The straight of acids in a following hydride in the order of.


Oxidation Number of central atom:-

In the case of hydroxide (acid) higher the oxidation number of central atom greater will be its acids nature because central atom with higher oxidation state has greater tendency to expect electron.

Ex. HclO4> HclO3>HclO2 >HCO


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