Chemistry - extra topics for jee mains


Chemistry Formulas

Class 11 chapter- environment chemistry

  • Pollutant : A substance released into the environment due to natural or human activity which effects adversely the environment is called pollutant.
  • Contaminant: A substance which is not present in the nature, but released during human or natural activity into environment is called contaminant.
  • Receptor: It is the medium which is affected by a pollutant.
  • Sink: Sink is the medium which retains and interacts with a long lived pollutant is called sink.
  • Dissolved oxygen (DO): The amount of O₂ present in H₂O in dissolved condition is called dissolved oxygen.
  • The optimum value of DO for good quality of water is 4 – 6 ppm (or) mg/lit.
  • Chemical oxygen demand (COD): The amount of O2 required to oxidize all the organic matter present in water is called chemical oxygen demand.
  • Bio chemical oxygen demand (BOD): The amount of Dissolved O2 used up by the micro organisms present in water during a 5-days period under anaerobic conditions is known as BOD.
  • BOD value for pure water is 3ppm.
  • Municipal sewage has BOD value 100 - 4000ppm.
  • BOD = Amount of oxygen/million parts by weight.
  • Threshold limit value (TLV): The minimum level of pollutants present in a mine (or) factory which adversely affect a person when exposed to these for 7-8 hrs in a day is known as TLV.
  1. Atmosphere
  2. Lithosphere.
  3. Hydrosphere
  4. Biosphere
  • Atmosphere: The gaseous layer around the earth is called atmosphere.
  • Troposphere (0-11km): Major portion of air is present in troposphere.
  • Stratosphere: (11-50km): Ozone is present in stratosphere which absorbs harmful U.V. rays.
  • Mesosphere: (50-85km) : Temp falls with an increase in altitude is mesosphere.
  • Thermospheres (85-500km): In the thermosphere temp raises with altitude. The water present in on and above earth constitutes hydrosphere.
  • Lithosphere Outer mantle of the solid earth is called Lithosphere.
  • Biosphere Living organisms and their interaction with the environment is called biosphere.
  • Acid rains are obtained due to oxides of nitrogen and sulphur.
  • Acid rain may have a pH of 4 – 5.
  • Green house effect: The progressive heating up of surface of the earth is called green house effect (or) global warming.
  • The green house gases are CFC’s, O3, NO and water vapour.
  • The chemicals responsible for depletion of ozone layer are chlorofluorocarbons (CFC’s), nitric oxide (NO) and chlorine (Cl2).
  • Eutrophication: Enrichment of water bodies with nutrients is called Eutrophication.
  • When fluoride concentration in water is greater than 3ppm, causes ‘fluorosis’.
  • In fluorosis, the fluoride in water react with calcium present in the body to form calcium chloride.
  • Waste water treatment : The process of removal of pollutants in waste water in called waste water treatment.
  • BOD of polluted water is high BOD of domestic sewage is around 165 ppm, industrial waste water is 200 ppm.
  • Prevention of environmental pollution :-
  1. Waste management
  2. Developing green Chemistry
  3. Controlling the growth of population
  4. Growing trees
  5. Creating Awareness of polluted environment


Chemistry Formulas

Class 12 chapter- chemistry in everyday life

Medicines or Drugs

Chemical substances used for treatment of diseases and for reducing suffering from pain are called medicines or drugs.


The treatment of diseases due to bacterial invasion by chemical compounds which destroy the micro-organism without affecting the tissues of the host is known as Chemotherapy.

The chemicals so used for the cure are called chemotherapeutic agents. Some of the medicinal compounds are described below :

  • Antipyretics: Chemical substances which are used to bring down the body temperature in high fevers are called antipyretics. Aspirin, paracetamol, analgin and phenacetin are some of the common antipyretics.

phenacetin reaction

  • Analgesics: Chemical substances used for relieving pain are called analgesics. Aspirin and analgin act both as antipyretics and analgesics. They give immediate relief from pain and fever. e.g. Novalgin is the most widely used analgesic.
  • Antiseptics: Chemical substances which prevent the growth of micro organisms or kill them but are not harmful to the living human tissues are called antiseptics. Antiseptics are applied to the living tissues. These are applied to wounds. ulcers and diseased skin surfaces. Some of the compounds used as antiseptics are exemplified below:
  1. Dettol, a mixture of chloroxylenol (also known as parachlorometaxylenol) and terpeneol, is a commonly used antiseptic for wounds, cuts, diseased skin surfaces, etc.
  2. Bithional is added to soaps to impart them antiseptic properties. Such soaps are used to reduce odour due to bacterial action on skin surface.
  3. Iodine is also used as an antiseptic in the form of tincture of iodine i.e., a 2-3% solution of iodine in alcohol-water.
  4. Hydrogen peroxide solution also has strong antiseptic properties


Chemical substances which kill micro organisms or stop their growth but are harmful to human tissue are called disinfectants. They are used to disinfect floors, toilets, etc. for example phenol(1%), sulphur dioxide, etc.


These are substance which are used for the treatment of stress and mental diseases. These effect the central nervous system and induce sleep to the patients. The tranquillizers are also called psycho-therapeutic drugs. Barbituric acid and its derivatives such as luminal, veronal and seconal are most commonly used tranquillizers. These derivatives of barbituric acid are known as barbiturates.