Ditte’s reaction in halogen chemistry
I2 O5 is a powerful oxidizing agent, which oxidize CO molecule in quantitative analysis to convert CO2 molecule along with molecular iodine .
Wednesday, January 22, 2020
I2 O5 is a powerful oxidizing agent, which oxidize CO molecule in quantitative analysis to convert CO2 molecule along with molecular iodine .
Wednesday, January 8, 2020
Halogen elements definition .
There are
few electronegative as well as non metallic elements ,belongs to 17th
group in the modern periodic table, are known as halogen elements . Halogen
elements are fluorine, chlorine, bromine , iodine and astatine .
Among these
, fluorine and chlorine are colourless
gaseous elements , bromine is brown color liquid and iodine is violet
crystalline solid.
The name
‘halogen’ means salt producing .That is
they produced salt , when react with
metals .The salts of first three occur in the sea water.
Such as sodium chloride ( NaCl ) , calcium fluoride (
CaF2 ), silver bromide ( AgBr ) and potassium iodide( KBr ) etc .
Halogen elements in periodic table.
According to
modern periodic table , group 17th comprises of five elements ,
namely , fluorine, chlorine, bromine ,iodine and astatine which do not occur free in the nature , are known
as halogen elements .
In deed , fluorine,
chlorine, bromine and iodine have closely related properties and are known collectively as the halogen elements.
Halogen elements properties
General
electronic configuration of halogen elements are, ns2,np5 .That is the outer most shell of halogen atom
contains seven electrons .
Hence halogen element have tendency to gain one more electron to complete their octet .
Hence halogen element have tendency to gain one more electron to complete their octet .
Consequently,
halogen elements are non metal as well as strong electronegative . The electronegativity
of halogen elements decrease as we move
from top to bottom along a group .
Halogen
elements have high affinity for
electron, that is have a strong tendency to pick up electrons . For this reason
, they exhibits strong oxidizing power .
They can oxidize metal as
well as non metal . Although ,the oxidizing power decrease on moving down the
group .
Halogen elements reactivity
All the
halogen elements react with metals as well as with many non metals to form halides. Fluorine is the most reactive among
the halogen elements.
The reactivity decreases when we move from top to bottom
along a group .
For example,
with sulfur fluorine forms sulfur
hexafluoride , chlorine forms sulfur tetrachloride , bromine forms sulfur
dibromide whereas iodine does not react at all .
Another
example of halogen elements reactivity are the interaction of halogens with
water .
Fluorine react with water fast with explosion to form a mixture of ozone and oxygen .
Chlorine react with water in presence of sunlight and bromine react so much less readily, while iodine scarcely reacts with water .
The chemical reactions of chlorine and bromine elements with water under specific condition is shown below,
Chlorine react with water in presence of sunlight and bromine react so much less readily, while iodine scarcely reacts with water .
The chemical reactions of chlorine and bromine elements with water under specific condition is shown below,
All the
halogen elements react with hydrocarbons but their reactivity decreases with
increase in atomic number .
Fluorine is most reactive towards hydrocarbons.
It decompose hydrocarbon and release
free carbon atom .
Chlorine under goes substitution reaction with hydrocarbon. Bromine also shows substitution reaction with hydrocarbon but slowly . Iodine
react with hydro carbon under condition
.
Halogen elements Uses
There are a
large number of use of halogens elements . Halogen elements used both in
organic as well as in inorganic chemistry .
In organic chemistry , halogen
elements participate in nucleophilic and in addition reaction to produced
a large number of halogen containing compounds .
In inorganic
chemistry there are a huge number
of halogenated compounds . Most important compounds of halogen elements are
Halogen
elements is used in many organic
reaction to produced halogenated
compounds . Iodine and bromine is used
as laboratory reagents .
Halogen
elements is also used in every day our
life . Such as chlorine is used to purify water .Chlorine is also a part of
table salt ( NaCl ) , which is most
widely used chemical compound.
Fluorine is
used in different fluorides , which are added to water supplies to protect our
tooth decay .
Fluorine is also used to hardiest our enamel to prevent tooth. HF is used in glass industry to prepare different type of glass .
Fluorine is also used to hardiest our enamel to prevent tooth. HF is used in glass industry to prepare different type of glass .
Chlorine
compound that is bleaching powder is used to prevent the growth of bacteria . Chlorine is also used in paper making industry and plastics industry .
Bromine is
in photography, to prepare medicine , in
water purification and to prepare pesticides
and flame resistant plastics .
Iodine is
used mainly in iodometric and iodimetric titration and to prepare medicine ( tincture of iodine ) .
Which is the
strongest acid among HF, HCl, HBr and HI ?
The acidic
strength of halogen acid depends on the degree of ionization in aqueous
solution and also bond dissociation energy .
Generally,
the degree of dissociation decreases with increasing bond dissociation energy .That is with increasing bond dissociation enthalpy, acidic strength decreases.
Since, the increasing order of bond dissociation energy of halogen acids are ,
Therefore,
the increasing acidic order of the above halogen acids are ,
Consequently,
among the halogen acids (, HF , HCl , HBr
and HI ), HI is the strongest acid .
Summary :
Halogen elements definition .
Halogen elements in periodic table .
Halogen elements properties .
Halogen elements reactivity .
Halogen elements uses .
Which is the strongest acid among HF, HCl , HBr and HI acid ?
Summary :
Halogen elements definition .
Halogen elements in periodic table .
Halogen elements properties .
Halogen elements reactivity .
Halogen elements uses .
Which is the strongest acid among HF, HCl , HBr and HI acid ?
Wednesday, January 1, 2020
Schotten Baumann reaction .
The benzoylation of phenol is carried out in presence of aqueous NaOH or pyridine solution . Because , Benzoyl chloride does not hydrolysed by base .
So, the
benzoylation of phenol in presence of aqueous NaOH solution gives phenyl acetate . This reaction is known as Schotten Baumann
reaction.
