2.3 ACID, BASIS AND SALTS
Part 3
Some Important substances
01. COMMON SALT: - It is known as common salt. Its chemical name is sodium chloride. Its chemical
formula is NaCl. It is used with food for taste. It is obtained from seas.
Dandi March or Salt Satyagrah of Gandhi’s was also connected with salt.
Preparation: - It is formed
by the reaction of hydrochloric acid and sodium hydroxide.
HCl +
NaOH ¾¾® NaCl
+ H2O
Uses: - It is used for making
of sodium hydroxide, baking powder, washing powder and as a raw material of
bleaching powder.
02. SODIUM HYDROXIDE: - Its chemical formulae is NaOH.
Preparation:- It is prepared by the help of electrolysis of
water solution of sodium chloride.
Electrolysis decomposed into the sodium hydroxide, chlorine gas and
hydrogen gas.
Electrolysis
2NaCl + 2H2O ¾¾¾® 2NaOH +
H2 + Cl2
At this time the
chlorine is released at [1]Anode and
hydrogen at [2]Cathode.
This process is also known as [3]chlor (Alkali)-base process.
Product of Sodium Hydroxide: - The products of Sodium Hydroxide are sodium hydroxide, chlorine gas and
hydrogen gas. Chlorine is released at Anode and hydrogen is at Cathode.
Chlorine: - It is used in
manufacturing of ammonium, Manures and to prepare of margarine gas.
Hydrogen Gas:- It is used in water and swimming pools
cleaning, to make P.V.C, as a insecticides or pesticides, it is also used in
manufacturing of C.F.C.
Sodium hydroxide:- It is used for making of soap, artificial discomposure, paper and making
of artificial fiber. It is also used to remove greases from the metals.
03. BLEACHING
POWDER : - The
chemical name of bleaching powder is calcium oxichloride. The chemical formula
of bleaching powder is CaOCl2 also known as chloride of lime
Manufacturing: It is manufactured by the help of
reaction of chlorine with dry slaked lime [Ca(OH)2] .( Dry Slaked lime is also called
as chloride of lime )
Ca(OH)2 +
Cl2 ¾¾® CaOCl2
+ H2O
Only
for knowledge :-
[It is manufactured in Hasenclever plant. It
consists of a number of horizontal cylinders in it with rotating shafts
carrying blades. The slake lime poured into the uppermost cylinder through
the hopper on revolving blades to down. The Cl gas, which released from the
lowest pipe react with the lime, which is, gets saturated with it. The slake
lime converted into bleaching powder, which we get into bottom.]
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Only
for knowledge :-
Reaction with Carbon Dioxide
CaOCl2
+CO2 = CaCO3 +Cl2
Reaction with Dilute Sulphuric Acid
CaOCl2
+H2SO4 = CaSO4 +Cl2 +H2O
Reaction with Dil HCl
CaOCl2
+2HCl = CaCl2 + Cl2 +H2O ]
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Properties: Bleaching powder is yellowish white powder with
chlorine smell; it loses its Cl into air. It is soluble in cold water.
Uses: ¶ For bleaching of
cotton, linen and paper in industries. ¶It is used for cleaning
water. ¶
In manufacturing of chloroform CHCl3, ¶ For making wool
unsinkable. ¶ It is used for whiteness of clothes in
laundries. ¶ It is used as a oxidizing agent in
chemical industries.
04.
BAKING SODA: It is the compound of
sodium. Its chemical formula is NaHCO3 and its chemical name is
Sodium hydrogen carbonate. On heating it turned into sodium carbonate or soda
ash.
Manufacturing
or Preparation: It is manufactured by
Solvay (Ammonia soda) process. It is the primary product of the Solvay process.
The raw material used in its manufacturing are Sodium Chloride NaCl (Common
salt), Ammonia (NH3) and Limestone (CaCO3)
NaCl + NH3 + H2O + CO2 ¾¾® NH4Cl
+ NaHCO3
Only
for knowledge :-
[In
this process the concentrated and cold
sodium chloride (Brine) saturated with Ammonia drooped from the top of carbonating tower (Solvay tower). The
tower contains perforated plates. And carbon dioxide is passed up into the
tower from the base formed by the burning of calcium chloride.(CaCO3
= CaO + CO2).]
In this process the Ammonium chloride and sodium hydrogen
carbonate is formed. Ammonical brine means the composition of sodium
chloride, ammonia and water.
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Properties:
It is White Crestline solid and
insoluble in water. The solution of baking powder is mildly alkaline. It is
salty in taste. It release CO2 on heating so it is used as a
constituents of baking powder and in effervescent drinks.
Uses: ¶ It is used as an antacid to remove acidity of the stomach. Being
alkaline it neutralizes the excess acid of stomach and relieves indigestion.
¶ It is used in making of soft drinks. ¶ It is used for making of sodium bicarb the medicine of stomach.
¶ Baking powder
is (the combination of sodium hydrogen carbonate and tartaric acid) heated then
it decomposed into sodium hydrogen carbonate, carbon dioxide and sodium
carbonate. So that it make spongy to the bread and cake. (Tartaric acid
neutralized the sodium carbonate other wise they will be biter in taste.) It is
used in cooking for the purpose of increasing the boiling point of water.
¶ It is used in fire extinguishers. There are solution
hydrogen carbonate and Sulphuric acid in it. When it mixed by pressing the knob
a lot of carbon dioxide gas is produced. The pressure of stream of CO2
gas forces a stream of effervescing liquid on the fire and cuts off the supply
of oxygen to fire.
¶ It is use to lowered the boiling point of water at
the time of boiling vegetables.
05.
WASHING SODA: It is the compound of
sodium. Its chemical formula is Na2CO3.10H2O.
Its chemical name is sodium carbonate decahydrate. It has 10 molecules of
water.
[Sodium
carbonate without water is called anhydrous sodium carbonate Na2CO3.
It is also known as soda ash.]
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Manufacturing
or preparation: It is manufactured by
Solvay (Ammonia soda) process. The raw material used in its manufacturing are
Sodium Chloride NaCl (Common salt), Ammonia (NH3) and Limestone
(CaCO3)
NaCl + NH3 + H2O + CO2 ¾¾® NH4Cl
+ NaHCO3
The
sodium hydrogen carbonate is slightly soluble in water and separated by
filtration. On heating it converted into sodium carbonate (soda ash) it is the
last product of Solvay Process.
2NaHCO3 ¾¾® Na2CO3 +
H2O + CO2
After
dissolving in water we get washing soda.
Na2CO3 +
10H2O ¾¾® Na2CO310H2O
Only
for knowledge :-
[Properties: - It is transparent crystalline solid. Its molecule
contains ten molecules of water of crystallization. It loses the water molecules
in the air.
It
is soluble in water. The solution of
washing soda in water is alkaline which turns red litmus to blue. It shows
efflorescence. On heating it loosed all the water of the molecules. It has
cleaning or detergent prorates.]
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Uses: ¶ It is used for
softening of hard water. ¶ It is used as a laboratory reagent. ¶ It is used in Laundry
as washing soda. So it is known as
cleaning agent. ¶ It is use in the formation of dry
washing powders. ¶ It is used in the manufacturing of soap,
glass, paper, baking powder, borax and caustic soda etc.
06.
PLASTER OF PARIS (CaSO4 ½
H2O): - Its chemical formula is (CaSO4 ½ H2O).
It is also called calcium sulphate hemi hydrate.
¶ About 5000 years ago Egyptians prepared it by heating
gypsum (calcium sulphate) in open air. It was manufactured in Monometer in
Paris first time so it called Plaster of Paris.
Manufacturing
or Preparation: It is obtained by
heating of gypsum [CaSO4.2H2O] at 3730K in the form of calcium sulphate
hemihydrates [CaSO4.½H2O].
3730K
CaSO4.2H2O ¾¾®CaSO4.½H2O+1½ H2O
It is white coloured
powder. It is collected carefully otherwise it will turn into calcium sulphate
after reaction with water.
CaSO4.½H2O
+ 1½ H2O¾¾® CaSO4.
2H2O
The heating should be controlled carefully otherwise anhydrous
calcium sulphate will produce which is different in properties.
Only
for knowledge :-
Properties: It is a white powder. After mixing in water it
converted into gypsum again.
CaSO4.½H2O + 1½ H2O¾¾® CaSO4. 2H2O
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Uses: ¶ It is used for making toys, decorative material, cheap ornaments,
cosmetics, blackboard chalk and casts for statues. ¶ It is also used to make fireproofing material. ¶ It is used in laboratories as sealing the apparatus. ¶ It is used for making plaster for setting the
fractured bone. ¶ It is used for finishing of statues. ¶ It is used to decorate the house in the form of
P.O.P. etc.
Water of Crystallization: - Water molecule present in crystalline solid is known
as water of crystallization.
Washing
powder [Na2CO310H2O]
contains ten molecules of water of crystallization, gypsum [CaSO4.2H2O]
contains two molecules of water of crystallization and copper sulphate [CuSO4.5H2O] contains five molecules of water of crystallization.
Efflorescence: The loss of crystallize water from any hydrated salt
into the air is called efflorescence.
Na2CO3.10H2O ¾¾® Na2CO3.H2O
+ 9H2O
2.2 ACID, BASIS AND SALTS (Part 3) With Notes
[1]
Anode = Negative Terminal
[2]
Cathode = Positive Terminal
[3]
Chlor (Alkali)-base process : - In the reaction of Sodium Chloride and
water the base (alkali) NaOH (Sodium Hydroxide) and Chlorine is formed so that
this process is termed or known as chlor (Alkali)-base process.
2NaCl
+ 2H2O ¾¾¾® 2NaOH
+ H2 + Cl2
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