General Knowledge - सामान्य ज्ञान (Chemistry - रसायन विज्ञान)

• Petrol को शिलातौल या ध्रुव स्वर्ण कहते है
• Sodium can burn in water
• Methanol fire can’t be seen by naked eye

Chemical Processes

Process	Definition	Usage
Electrolysis	It is a process in which electric current is passed through a substance to effect a chemical change.	Electroplating, Production of pure form of some metals
Saponification	It is a process of converting fat into soap by treating it with an alkali.	Manufacture of soaps
Fermentation	It is a metabolic process in which sugar or carbohydrate is converted to acid, gas or alcohol.	Making of wine, liqour, curd etc.
Vulcanisation	It is a process in which natural rubber is treated with sulphur to make it more durable and elastic.	Manufacture of tyres
Emulsification	It is a process in which large fat globules are broken down into tiny droplets. The tiny droplets are uniformly distributed in an immiscible liquid to form emulsion.	Emulsions are used in paints, cosmetics, medicines etc.
Sublimation	It is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase.	Used in frost-free refrigerators
Pasteurisation	It is a heat treatment process to kill bacteria in liquid food or beverages.	Preservation of milk
Carbonation	It is a process of mixing carbondioxide in liquids under high pressure.	Making of soft drinks
Distillation	It is a process of separating the component substances from a liquid mixture by selective evaporation and condensation.

Important Organic Acids

Name	Chiefly found in	Formula
Lactic acid	Sour milk	C2H4OHCOOH
Acetic acid	Vinegar	CH3COOH
Formic acid (Methanoic acid)	Ant venom	HCO2H
Citric acid	Citrus fruits like lemon, lime, orange	C6H8O7
Oxalic acid	Rhubarb, spinach	H2C2O4
Butyric acid	Milk, butter	CH3CH2CH2-COOH
Lauric acid	Coconut oil	CH3(CH2)10COOH
Malic acid	Sour apples, sour grapes	HO2CCH2CHOHCO2H
Tartaric acid	Grapes, tamarinds, pineapples	C4H6O6
Erucic acid	Rapeseed oil, Mustard oil	CH3(CH2)7CH=CH(CH2)11COOH

Properties of Acids

1. Acids have pH less than 7.
2. Acids turn blue litmus to red.
3. Acids have sour taste.
Reactions
With bases	Acids react with bases to produce a salt and water.
With carbonates	Acids react with carbonates to produce salt, water and carbon dioxide.
With metals	Acids react with metals to produce a salt and hydrogen.

Important Inorganic Acids

Name	Formula	Common Use	Also remember
Hydrochloric acid	HCl	Pickling of steel	Gastric acid secreted by stomach mainly contains HCl.
Nitric acid	HNO3	Production of fertilisers	Nitric acid is produced by electric discharge in the atmosphere such as lightning. Known as Aqua Fortis in ancient times.
Sulphuric acid	H2SO4	As an electrolyte in lead-acid batteries.	Known as Oil of Vitriol in ancient times.
Phosphoric acid	H3PO4	Used in beverages like colas to give a tangy taste.	-
Hydroflouric acid	HF	Etching (writing or marking) of glass	Stored in plastic containers.
Carbonic acid	H2CO3	Making of soft drinks and other bubbly drinks	CO2 in air combines with water in the ocean to form carbonic acid. Ocean acidification thus caused is of grave environmental concern.
Boric acid	H3BO3	1. Antiseptic 2. Eye wash 3. Socks and shoes to prevent athlete's foot

Important and Useful Chemicals

Use	Chemical
Chemical with which flourescent lamps are coated for providing illumination	Phosphor
Chemical used to remove rust stains from clothes	Oxalic acid
Chemical with which photographic films are coated	Silver Bromide
Chemical in which gold dissolves	Aqua Regia
Chemical with which non-stick cookware is coated	Teflon
Chemical used in the manufacture of matches	Phosphorus
Chemical used to purify water (as a disinfectant)	Chlorine
Chemical used as an antiseptic in mouth freshner, toothpastes etc.	Hydrogen Peroxide
Chemicals used in the breath test to check drunken driving	Potassium dichromate and Sulphuric acid
Chemical used as a purgative	Magnesium Sulphide
Chemical used in cloud seeding	Silver Iodide
Chemical used as a fixing agent in photography and also for washing as a germicide	Sodium thiosulphate
Chemical commonly used in explosive devices as well as fertilisers	Ammonium Nitrate
The substance which is used to make capsule shells in pharmaceutical industry. The substance is also used as gelling agent in cooking.	Gelatin
The sugarcane industry product being blended with petrol to reduce pollution and also to reduce the import burden of petrol in India	Ethanol
The organic compound widely used as a cleaning agent in dry cleaning	Tetrachloroethylene (perchloroethylene)
The chemical commonly used in baby diapers for its super absorbent properties	Sodium polyacrylate
The chemical used for embalming bodies and preservation of animal specimens and tissue samples	Formalin (aqeous solution of formaldehyde)
The compound which is used in moisturing creams and soaps because of its hygroscopic properties	Glycerol
The chemicals used to produce fog/smoke on theatrical stages or studios	1. Dry ice 2. Glycol and water mix
The chemical used as anticoagulant in blood collection tubes and for the preservation of blood in blood banks	Sodium Citrate
The chemical commonly used as rodenticide	Zinc Phosphide
The chemical commonly used in sunscreen lotions, cigarette filters, ceramic industry	Zinc Oxide

Common and Scientific Names of Chemicals

Sodium Compounds

Common Name	Chemical Name	Formula
Washing soda	Sodium carbonate	Na2CO3
Baking soda	Sodium bicarbonate	NaHCO3
Borax	Sodium tetraborate decahydrate	Na2B4O7·10H2O
Brine	Aqueous sodium chloride solution	NaCl
Caustic soda	Sodium hydroxide	NaOH
Hypo	Sodium thiosulfate	Na2S2O3

Calcium Compounds

Common Name	Chemical Name	Formula
Bleaching powder	Calcium hypochlorite	Ca(ClO)2
Quick Lime	Calcium oxide	CaO
Marble	Calcium carbonate	CaCO3
Plaster of paris	Calcium sulfate	CaSO4
Chalk	Calcium carbonate	CaCO3
Gypsum	natural Calcium sulfate	CaSO4

Common and Scientific Names of Chemicals

Sodium Compounds

Common Name	Chemical Name	Formula
Washing soda	Sodium carbonate	Na2CO3
Baking soda	Sodium bicarbonate	NaHCO3
Borax	Sodium tetraborate decahydrate	Na2B4O7·10H2O
Brine	Aqueous sodium chloride solution	NaCl
Caustic soda	Sodium hydroxide	NaOH
Hypo	Sodium thiosulfate	Na2S2O3

Calcium Compounds

Common Name	Chemical Name	Formula
Bleaching powder	Calcium hypochlorite	Ca(ClO)2
Quick Lime	Calcium oxide	CaO
Marble	Calcium carbonate	CaCO3
Plaster of paris	Calcium sulfate	CaSO4
Chalk	Calcium carbonate	CaCO3
Gypsum	natural Calcium sulfate	CaSO4·2H2O

Other Compounds

Common Name	Chemical Name	Formula
Alum	Aluminium potassium sulfate	KAl(SO4)2.12H2O
Aqua regia	Nitrohydrochloric acid	HNO3 + 3 HCl
Aspirin	Acetylsalicylic acid	C9H8O4
Corundum (ruby, sapphire)	Aluminium oxide	Al2O3
Dry ice	Solid Carbondioxide	CO2
Epsom salts	Magnesium sulfate	MgSO4·7H2O
Heavy Water	Deutrium oxide	2H2O or D2O
Pearl Ash	Potassium carbonate	K2CO3
Plumbago	Graphite	C
Prussic acid	Hydrogen cyanide	HCN
Jeweller's rouge	Ferric oxide	Fe2O3
Saltpeter	Potassium nitrate	KNO3
Table sugar	Sucrose	C12H22O11
Talc or talcum	Magnesium silicate	Mg3Si4O10(OH)2
Vinegar	Acetic acid	CH3CO2H

Important Scientific Laws

Avogadro's Law (Gases) It states that equal volumes of gases at the same temperature and pressure contain the same number of molecules regardless of their chemical nature and physical properties. This number (Avogadro's number) is 6.022 X 1023. It is the number of molecules of any gas present in a volume of 22.41 litres and is the same for the lightest gas (hydrogen) as for a heavy gas such as carbon dioxide or bromine. Stated in 1811 by the Italian chemist Amedeo Avogadro (1776-1856) Boyle's Law (Gases) For a fixed amount of an ideal gas kept at a fixed temperature, P [pressure] and V [volume] are inversely proportional (while one doubles, the other halves). In other words product of the pressure and volume is exactly a constant for an ideal gas. Propounded by Robert Boyle, an Irish Chemist in 1662 Charles' Law (Gases) It states that the volume of a gas is directly proportional to the temperature of the gas, provided the amount of gas and pressure are held constant. It was first published by French natural philosopher Joseph Louis Gay-Lussac in 1802, giving credit to an unpublished work from the 1780s by Jacques Charles. It is also known as Gay-Lussac Law.

Coulomb's Law (Electrostatics) The magnitude of the Electrostatics force of interaction between two point charges is directly proportional to the scalar multiplication of the magnitudes of charges and inversely proportional to the square of the distances between them. Published in 1783 by French physicist Charles Augustin de Coulomb Faraday's Law of Electromagnetic Induction The induced electromotive force (EMF) in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit. Published by English Physicist Michael Faraday in 1831. Hooke's Law of Elasticity It states that, for relatively small deformations of an object, the displacement or size of the deformation is directly proportional to the deforming force or load. Discovered by the English scientist Robert Hooke in 1660. Joule's Law (Electricity) It states that, heat produced by an electric current is directly proportional to the resistance of the conductor, the square of the current, and the time for which it flows. Given by the English physicist James Prescott Joule around 1850.

Welding

It is process for joining similar metals by melting and fusing the base metals as well as the filler metal. Welding is usually used with ferrous-based metals such as steel and stainless steel. The temperature range of welding is 800ºC - 1635ºC. Welded joints are the strongest of joints.

Brazing

It is a process in which two close-fitting parts are joined by using a filler material which is heated above its melting point and distributed in the gap by capillary action. A chemical cleaning agent known as flux is used to prevent oxidation of metals being heated. Temperature range for brazing is above 450ºC.

Soldering

It is a process similar to brazing but the filler material is of much lower melting point. The filler material, solder is an alloy of tin and lead. Temperature range for soldering is below 450ºC. Soldered joints are the weakest of the three viz welding, brazing and soldering.

Electroplating

It is process in electric current is used to deposit ions of a metal on another. Thus chromium may be used to plate iron bars. Electroplating is usually done to prevent corrosion of the base metal or for decorative purpose.

Smelting

It is a process of extracting a metal from its ore by heating the ore beyond its melting point. Flux is used in the process to remove the slag

Metal processes

Annealing

It is a process in which a metal is heated to a specific temperature and then cooled slowly in order to make the metal soft enough for easy cutting and shaping.

Hardening

It is a process in which a metal is heated to a specific temperature and then cooled suddenly in order to make the metal hard. This also makes the metal brittle or easy to break.

Tempering

It is a process in which a hardened metal is heated to a specific temperature and then cooled slowly in order to make the metal tough enough for use as cutting or abrading tool. Tools such as drills, chisels, files etc. are hardened and tempered.

Galvanisation

It is a process in which a protective zinc coating is applied on iron to prevent it from rusting.

Ores of Metals

Metal	Ore
Aluminium	Bauxite
Beryllium	Beryl
Chromium	Chromite
Cobalt	Cobaltite
Copper	Bornite, Chalcocite
Gold	Quartz
Iron	Magnetite
Lead	Galena
Manganese	Pyrolusite
Mercury	Cinnabar
Nickel	Pentlandite
Tin	Casseterite
Tungsten	Wolframite, Scheelite
Silver	Argentite
Uranium	Uraninite
Zinc	Sphalerite

Important Alloys

Alloy	Combination of
Duralumin	Aluminium and Copper
Brass	Copper and Zinc
Bronze	Copper and Tin
Invar	Iron and Nickel
Stainless steel	Iron, Chromium and Nickel
German Silver	Copper, Nickel and Zinc
Gunmetal	Copper, Tin and Zinc
Solder	Lead and Tin
Electrum	Gold and Silver
Constantan	Copper and Nickel
Manganin	Copper, Manganese and Nickel
Manganin is a trademarked name.

Facts about Metals

Fact to remember	Name of the metal
The metal with the highest melting point	Tungsten
The metal with the highest thermal conductivity	Silver
The metal with the highest electrical conductivity	Silver
The metal with the highest density	Osmium
The metal with the lowest density	Lithium
The most malleable and ductile metal	Gold
The least reactive metal	Platinum
Metal most abundant in earth’s crust	Aluminium
Metal which forms amalgam with other elements	Mercury
Metal used in a fuse wire and also in solder	Lead-tin alloy
Metal used in the filament of a bulb	Tungsten
Metal which pollutes the air of cities having large number of vehicles	Lead (reason for using unleaded petrol)
Metal used in the filaments of electric heaters	Nichrome
Metal used as radiation shield	Lead
Metal into which Uranium turns when it loses all its radioactivity	Lead
Metal used for making boats because it does not corrode by seawater	Titanium

Gases - Facts to Remember

Fact to remember	Name of the gas
Gas most abundant in earth's atmosphere	Nitrogen (78%)
Percentage of oxygen in earth's atmosphere	21% (appx)
The lightest gas	Hydrogen
The heaviest gas	Radon
Tear Gas	Ammonia (NH3)
Marsh gas	Methane
Laughing gas	Nitrous Oxide (N2O)
Natural gas	Mainly methane with small quantities of ethane and propane
Gobar gas	Methane, CO2 and hydrogen
Gas with foul smell	Hydrogen Sulphide (H2S)
Gas mixed with oxygen and given to patients with restricted breathing	Helium
A major air pollutant, the percentage presence of which is checked in vehicle pollution test	Carbon monoxide
The gas which is responsible for the formation of brown air in traffic congested cities	Nitrogen Dioxide
Major gaseous pollutant of areas located near thermal power station	Suphur dioxide
Strong smelling substance added to LPG	Ethyl Mercaptan or Ethanethiol
Gases responsible for depletion of ozone layer	Chloroflouro carbons
Gas responsible for acid rain	Sulphur dioxide
Gas used in gas welding and also artificial ripening of fruits	Acetylene
Gas used in electric bulbs	Argon
Gas used in flourescent lamps	Mercury vapour
Gas used in LPG	Butane, Propane and Ethane
Gas used in refrigeration	Freon (Diflouro Dichloro Methane)
Gas used as an anaesthetic in dental surgery	Nitrous Oxide

Facts about Periodic Table

The Periodic Table was created by Dmitry Mendeleyev, a Russian chemist and professor in 1869.

The Periodic Table has seven rows or periods.

The present Periodic Table has room only for 118 elements.

Lanthanides is a group of 15 elements from atomic number 57 to 71. Together with Scandium and Yttrium they are known as rare earth elements.

Rare earth elements which are 17 in number are actally not rare. Most of them are commonly found

Actinides is a group of 15 elements from atomic number 89 to 103. All actinides are radioactive.

The Periodic Table has 18 columns or groups. Some important groups are listed below.

Group 1 - Alkali metals or Lithium group consists of Lithium, Sodium, Potassium, Rubidium, Cesium and Francium. Hydrogen is not an alkali metal even though it is listed in the first column.

Group 2 - Alkaline earth metals or Beryllium group consists of Beryllium, Magnesium, Calcium, Strontium, Barium and Radium.

Group 15 - Pnictogens or Nitrogen group consists of Nitrogen, Phosphorus, Arsenic, Antimony, Bismuth and Moscovium.

Group 16 - Chalcogens or Oxygen group consists of Oxygen, Sulphur, Selenium, Tellurium, Polonium and Livermorium.

Group 17 - Halogens or Flourine group consists of Flourine, Chlorine, Bromine, Iodine, Astatine and Tennessine.

Group 18 - Noble gases or Helium or Neon group consists of Helium, Neon, Argon, Krypton, Xenon, Radon and Oganesson.

Facts about Elements

Fact to remember	Name of the element
An element is defined by the IUPAC as a pure chemical substance composed of atoms with the same number of protons in the atomic nucleus. All atoms of an element have the same number of protons.
Atoms of elements can have different number of electrons and neutrons.
A variant of an element with different number of neutrons is known as its	Isotope
Different physical form of an element is known as its (e.g. graphite and diamond)	Allotrope
Element most abundant in the Universe	Hydrogen
Element most abundant in the human body	Oxygen
Element which forms more than 10 million compounds	Carbon
Element with the lowest melting and boiling point	Helium
Element with the highest melting point	Carbon
Element with the highest boiling point	Tungsten
Element with highest density	Osmium
Element with lowest density	Hydrogen
Element with highest electronegativity	Flourine
Element with lowest electronegativity (highest electropositivity)	Francium
The first element to be produced artificially	Technitium
The most corrosion resistant element (which cannot be affected by water, chemicals or acids)	Iridium
The element which was discovered on the Sun before it was found on the Earth	Helium
The non-metallic element which is liquid at room temperature	Bromine
The metallic element which is liquid at room temperature	Mercury
The most reactive element	Flourine