Chemistry is a subject which never fails to annoy students, But we are here to provide short notes about some compounds which are very important from chemistry's point of view.
So ,without any further ado...
LETS GET STARTED !!!
SODIUM CHLORIDE:-
white crystalline solid
insoluble in alcohol
pure NaCl is not hygroscopic.it is hygroscopic due to impurities.
used in 'salting' out of soap and making freezing mixtures.
SODIUM HYDROXIDE:-
prepared by chlor-alkali process. It is generally formed near cathode.
It is deliquescent in nature.
It is a white crystalline solid.
It is corrosive
It is sparingly soluble in alcohol. However, KOH is fairly soluble in alcohol.
On exposure to atmosphere, it absorbs CO2 and forms sodium carbonate
carbon monoxide is neutral but it shows acidic nature with NaOH
sodium hydroxide break down protein to a pasty mass
it is also called soda lye.
SODIUM CARBONATE:-
most important chemical of commercial use.
Na2CO3.H2O is also known as crystal carbonate
The first process for manufacture of Na2CO3 was invented by Le-blanc.
However, the modern process is Solvay's process.
It is a white crystalline solid
Anhydrous sodium carbonate does not decompose on heating even to redness.
Soluble in water with evolution of considerable amount of heat.
The mixture of sodium carbonate and silica on fusion gives sodium silicate and carbon dioxide
sodium silicate:- Na2SiO3
sodium silicate is also called water glass or soluble glass.
used in softening of water as washing soda.
It is also used in textile and petroleum refining
Na2CO3.NaHCO3 :- sodium sesquicarbonate. It is neither efflorescent nor deliquescent.
Sodium sesquicarbonate is used in wood washing.
SODIUM BICARBONATE:-
normal carbonate can be changed to bicarbonate by passing CO2 through its saturated solution.
gives yellow color with methyl orange but no change with phenolphthalein and thus, it is a weak base.
used in making effervescent drinks.
used for production of CO2
CALCIUM CARBONATE:-
It is a white powder, insoluble in water.
It exists in nature as limestone, marble, chalk, etc.
It is used as flux in smelting of iron and lead ores.
CALCIUM SULPHATE:-
CaSO4.2H2O is also known as alabaster.
CaSO4 on heating strongly, decompose to give calcium oxide.
It forms calcium sulphide on strong heating with carbon.
CaSO4 + C -----> CaS + CO
In anhydrous form, it is used as drying agent.
CALCIUM SULPHATE HEMIHYDRATE:-
It is also known as Plaster Of Paris.
It is insoluble in water.
(DID YOU KNOW:- "the setting of cement is exothermic")
Setting of cement is catalyzed by sodium chloride
The hardened form of CaSO4.2H2O is in monoclinic form
Addition of alum to plaster of Paris is known as Keene's cement
CALCIUM OXYCHLORIDE:-
It is also known as Bleaching Powder.
It forms a milky suspension when dissolved in water
On standing, chlorine percentage decreases regularly.
chlorine is liberated with CO2 also
reacts with limited quantity of acid to release nascent oxygen
reacts with excess amount of acid to release chlorine
used for making wool unshrinkable
COMMON NAMES:-
CuSO4.5H2O :- blue vitriol
FeSO4.7H2O :- green vitriol
K2SO4.Al2(SO4)3.24H2O:- potash alum
ZnSO4.7H2O:- white vitriol
Na2SO4.10H2O :- Glauber's salt
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