2. Sodium Chloride (NaCl)
synonym : Rock salt, Common salt, table salt
Methods of preparation
1. From rock salt : A brine solution is prepared with bore holes drilled in the rock salt strata (layer) & water is run.
With the pressure of water, salt gets dissolved in water. Now thus brine solution is filtered because it contain some
impurities of strata. The filtrate brine is evaporated to obtain pure NaCl
2. From sea water : Sea water is firstly clarified by filtration to remove other impurities. Then common salt is
prepared by evaporation of salty water in a shallow tanks or pans
3. Laboratory method : in laboratory, on small scale it is prepared by acid-base reactions between a strong acid
(HCl) and a strong base (NaOH). The sodium chloride that is formed is recovered by evaporation of water
Properties
Physical : Occurs as white solid, odourless, anhydrous crystals. It is freely soluble in water, less soluble in alcohol
Chemical : 1) with silver nitrate solution, it gives white precipitates of silver chloride
3. Cont.
2) It reacts with sulphuric acid to give hydrochloric acid gas, this method is commonly used in laboratory for the
preparation of HCl solution
Assay : it is based on argentometric titration. Accurately weigh 0.1 gm of substance & dissolve it in 50 mL
of water in a stoppered conical flask. Add 1 mL of Potassium chromate as an indicator into that flask and
titrate the sample solution with previously standardize 0.1 N silver nitrate solution until Reddish-brown colour
appears which indicates the end point of the titration.
Uses : 1. it is used as an electrolytic replenisher, emetic and topical anti-inflammatory agent
2. 0.9 % (w/v) of NaCl solution is isotonic with blood that is used in eye drops, nasal drops etc.
3. it is also an ingredient of ORS with combination to other salts & glucose
4. Because of its emetic action it is used as an antidote in case of poisoning as a first aid
5. In dermatological preparations, it is used as a hydrating agent
4. Calcium Gluconate
synonym : Calcium D-Gluconate, Calcium salt of gluconic acid
Method of preparation
Calcium gluconate is prepared by boiling the solution of gluconic acid with excess of Calcium carbonate. The
ppt. obtained is then filtered and product is then concentrated to crystallization
Properties
Physical : Occurs as white, odourless, crystalline powder, soluble in water & insoluble in alcohol or other
solvent, It losses water with decomposition on heating
Chemical : 1. Its aqueous solution has a pH between 6 to 7
2. Calcium salt can form complex with many drugs which leads to the formation of precipitates
3. It is found to be incompatible with oxidizing agents, its solution get precipitated by oxalates,
borates etc.
5. Assay : As per I.P. , calcium gluconate may be assayed by complexometric titration involving replacement
with magnesium, using 5 mL of standard magnesium sulphate solution. The pH can be adjusted with
ammonia-ammonium chloride buffer. The volume of standardized disodium edetate is measured which is
used as primary standard. Here, Mordant black Ⅱ is used as an indicator.
Uses : 1. It is used as calcium replenisher
2. It is used for the treatment of hypo-calcemic tetany
3. Its injection is found to be useful in the treatment of black widow spider bite & urticaria
4. It is used in the treatment of burn from hydrofluoric acid
5. Its tablet is used as supplementary diet
Cont.
6. Ammonium Chloride (NH4Cl)
synonym : Salmiac, Amchlor, Ammonium muriate
Methods of preparation
1) It is prepared by neutralizing hydrochloric acid with ammonia, the resulting solution of ammonium chloride
is evaporated to dryness
2) It is also prepared by treating ammonium sulphate with sodium chloride
Properties
Physical : It is white, odourless, fine crystalline powder. It is Hygroscopic in nature& freely soluble in water
but slightly soluble in alcohol.
Chemical : In its vapour form, it dissociates in ammonia and hydrochloric acid
7. Cont.
Assay : Ammonium chloride is assayed by acid-base titration. The neutral formaldehyde solution is added
so that ammonium chloride will be converted to methyleneimine and hydrochloric acid. The liberated HCl
acid is titrated with previously standardized 0.1 (N) NaOH solution using phenolphthalein as an indicator
Uses : 1. Ammonium chloride is used as a systemic acidifier for the treatment of systemic alkalosis
2. It is used as an ingredient in expectorant cough syrup
3. It is given for its diuretic action especially to help the excretion of over dosage of basic drugs such
as amphetamine and in the treatment of lead poisoning by increasing its excretion
8. Sodium Bicarbonate (NaHCO3)
synonym : Sodium hydrogen carbonate, Baking soda, Meetha soda
Methods of preparation
1) Solvay ammonia process : In this process, carbon dioxide is passed through a solution of common salt in ammonia
water which leads to the precipitation of sodium bicarbonate with ammonium chloride. Due to higher solubility of
ammonium chloride in water, it remains in solution while sodium bicarbonate is less soluble in water and hence gets
precipitated out in the presence of ammonium bicarbonate
Step 1 : Formation of ammonium bicarbonate
Step 2 : Formation of sodium bicarbonate
2) Laboratory Method : Sodium bicarbonate is prepared from sodium carbonate. A solution of sodium carbonate is
saturated with carbon dioxide, the reaction mixture is then cooled which results in precipitation of sodium bicarbonate
Properties
Physical : Exists as white crystalline, odourless powder, it is soluble in water to small extent and insoluble in alcohol
It is stable in dry air and decomposed in moist air, it is alkaline to litmus
9. Cont.
Chemical : 1) On heating, it decomposes into sodium carbonate, carbon dioxide and water
2) On reacting with acid, it forms salt
Assay : The assay of Sodium bicarbonate is based on acid-base titration. Here, sodium bicarbonate is
titrated against 1 (N) HCl solution and methyl orange is used as an indicator. The end point is detected when
the solution turns into orange colour.
Uses : 1. It is used as an antacid to neutralize excess of gastric hydrochloric acid
2. It is used as electrolyte replenisher
3. Its 5 % solution is used in ear drops for softening of ear wax
4. Its 3.5 % solution in warm water is used in eye lotion
5. It as an ingredient in effervescent antacid preparation, e.g. ENO
6. It is specific for the treatment of systemic acidosis
10. Hydrogen Peroxide (H2O 2)
synonym : dihydrogen dioxide, oxydol
Methods of preparation
1) It is prepared by adding barium peroxide in an ice cold dilute sulphuric acid, the insoluble barium sulphate is
filtered off to get hydrogen peroxide
2) Hydrogen peroxide can be prepared by reaction of barium peroxide with phosphoric acid, here barium phosphate is
filtered off to get hydrogen peroxide
3) Now a days, most of the hydrogen peroxide is prepared by the electrolysis of ice-cold 50 % sulphuric acid.
Perdisulphuric acid is formed which on distillation under reduce pressure gives hydrogen peroxide
11. Cont.
4) ) It can also be prepared by treating sodium peroxide with dilute sulphuric acid, sodium sulphate crystallises out &
hydrogen peroxide is distilled under reduce pressure
Properties
Physical : 1) Hydrogen peroxide is colourless & odourless liquid
2) It acts as both oxidizing and reducing agent & is miscible with water
3) It readily gets decomposed when come in contact with oxidisable matter & the decomposition is
promoted by some metal catalysts such as Cu, Fe, Mn
Assay : The assay of hydrogen peroxide can be done by redox titration method. hydrogen peroxide & potassium
permanganate both are oxidizing agents and each other with the evolution of gaseous oxygen. Hydrogen peroxide
reduces KMnO4 solution & causes its decolourization. At the end point, excess drops of KMnO4 give pink colour,
here KMnO4 itself act as an indicator.
12. Cont.
Uses : 1) It is a strong antiseptic and destroys all pathogenic bacteria
2) 6 % solution of hydrogen peroxide is used as disinfectant. Its action is due to quick release of
oxygen from it when it is applied to tissues
3) It is used for cleaning of cuts and wounds
4) It is also used for removing ear wax
5) It is an effective antidote for phosphorous and cyanide poisoning
6) Its 1.6 % solution is used as deodorant, gargles and mouth wash
7) It is used for bleaching the hair
13. Chlorinated Lime (CaOCl2)
synonym : Bleaching powder, Chloride of lime, calcium hypochlorite
Method of preparation
Chlorinated lime is prepared by the action of chlorine on calcium hydroxide. Calcium hydroxide (slaked
lime) is spread on shelves in a suitable container. Then, the chlorine gas is introduced at the top of the
chamber and then allowed to pass through the contents of the shelves. This is usually carried out at 25 oC
temp. and this process takes about 12-14 hours.
Properties :
1) It is a dull white powder with characteristic odour
2) When it is exposed to air, it absorbs moisture and gradually decomposed
3) When bleaching powder is put in water, hypochlorite goes out in solution and the bleaching & oxidizing
properties have been shown
14. Cont.
Assay : The assay of chlorinated lime is based on redox titration method. Chlorinated lime liberates the
available chlorine as chlorine gas by the action of acid. Then, the free chlorine is allowed to react with
potassium iodide to liberate iodine, then, the quantity of liberated iodine is estimated by titration with 0.1 (N)
sodium thiosulphate (Na2S2O3) employing starch mucilage as an indicator
Uses : 1) Chlorinated lime has bactericidal action
2) It is used as disinfectant in wounds
3) It is also used as an ingredient in the preparation of detergents
4) It is a powerful bleaching agent and is used in decolourizing most of the dyes
15. Copper sulphate (CuSO4.5H2O)
Synonym : Blue vitriol, Cupric sulphate
Method of Preparation
The preparation of copper sulphate employs two step reactions. In the first step, copper granules are heated with
sulphur, a mixture of copper sulphate and cupric oxide (CuO) is obtained. The resulting solution is then filtered to
separate copper sulphate crystals
In the second step, the cupric oxide (CuO) is again treated with dilute sulphuric acid to convert it completely into copper
sulphate
Properties
Physical : Exists as deep blue colour crystals of pentahydrate, shows effervescence in dry air slowly, soluble in water
& insoluble in alcohol, it is acidic in nature, it changes blue litmus red.
Chemical : 1) On heating at 100 oC, it loses two molecules of water, at 140 oC, another molecule of water and at 200
oC, a white anhydrous salt is formed
16. Cont.
2) At very high temperature, it decomposes to cupric oxide & sulphur dioxide gas
Assay : The principle involved in the assay of copper sulphate is oxidation-reduction reaction. This reaction
is based on the instability of cupric iodide formed in the reaction of copper sulphate with potassium iodide,
which decomposes to give cuprous iodide with the liberation of free iodide. These liberated iodine is then
titrated with sodium thiosulphate solution using starch as an indicator. The titration is continued until blue
colour disappears.
Uses : 1) it is used as an emetic but in large doses, it is corrosive in nature
2) It is considered as a chemical antidote in phosphorous poisoning
3) Externally, it is used as an astringent and fungicidal (1.5 % solution)
4) It is used in the detection of water and in the preparation of absolute alcohol
5) It is an ingredient of Benedict's and Fehling’s reagent
17. Ferrous sulphate (FeSO4.7H2O)
Synonym : Green vitriol, Iron vitriol
Methods of Preparation
1) Ferrous sulphate is obtained by adding slight excess of iron to dilute sulphuric acid, iron gets dissolved to form
ferrous sulphate and hydrogen gas is evolved. The liquid is then concentrated & cooled to get crystals
2) On commercial basis, it is obtained by exploring moist iron pyrite (FeS2) to air, it gets oxidized slowly and forms
ferrous sulphate
Properties
Physical : Occurs as odourless bluish-green crystals or powder, it effloresces in dry air, On exposure tom moisture
, it gets oxidized and becomes brown in colour, it is completely soluble in water and insoluble in alcohol
Chemical : 1) On heating, it decomposes to ferric oxide, sulphur dioxide and sulphur trioxide
2) It decolorizes acidified potassium permanganate and turns acidified potassium dichromate green
18. Cont.
3) It reduces the salt of silver and gold into their corresponding metals
Assay : The assay of ferrous sulphate is based upon the principle of oxidation-reduction reaction, where the
ferrous sulphate is titrated against the previously standardized 0.1 (N) potassium permanganate solution in
acidic environment. Here potassium permanganate acts as self indicator.
Uses : 1) It is used as haematinic i.e. promote the formation of haemoglobin
2) It is used in the treatment of anaemia caused by iron deficiency
3) It also possesses disinfectant property
4) It is used as an insecticide in agriculture
5) It is used in the manufacturing of ink and in photography
19. Sodium Thiosulphate (Na2S2O3.5H2O)
Synonym : Sodium hyposulfite, anti-chlor
Methods of Preparation
1) Sodium thiosulphate can be prepared by boiling sodium sulphite with sulphur
2) It can also be prepared by passing SO2 gas in a mixture of sodium sulphide (8%) and sodium carbonate (6%)
3) Sodium thiosulphate can be prepared by reacting sodium hydroxide with sulphur
4) It can also be prepared by passing sulphur dioxide into sodium sulphide solution
Properties
Physical : Occurs as transparent prismatic crystalline powder, it effervesces in dry air, partially soluble in water and
insoluble in alcohol, it starts melting at 50 oC and at 100 oC, losses its all moles of water
Chemical : 1) Its aqueous solution decomposes slowly into sodium sulfide and sulphur
20. Cont.
2) Sodium thiosulphate is used to dissolve silver halide, that’s why it is used in photography
3) Barium chloride reacts with sodium thiosulphate solution to give white precipitates of barium thiosulphate
Assay : The assay of sodium thiosulphate is based upon iodimetric titration. Here, the sodium thiosulphate solution
is titrated against standard iodine solution using starch solution as an indicator. At the end point, the blue colour
disappears when all the iodine is reacted with sodium thiosulphate.
Uses : 1) It is used as an antioxidant
2) It is basically used as antidote in cyanide poisoning intravenously
3) Topically, it is used as an anti-fungal agent
4) It is used as a standard titrant in iodometric analysis
5) It is used as a fixer in photographic work
6) In textile industry, it is used as antichlor in bleaching process
