Course Content
Section Name Topic Name 3 Classification of Elements and Periodicity in Properties 3.1 Why do we Need to Classify Elements ? 3.2 Genesis of Periodic Classification 3.3 Modern Periodic Law and the present form of the Periodic Table 3.4 Nomenclature of Elements with Atomic Numbers > 100 3.5 Electronic Configurations of Elements and the Periodic Table 3.6 Electronic Configurations and Types of Elements: s-, p-, d-, f – Blocks 3.7 Periodic Trends in Properties of Elements
Section Name Topic Name 7 Equilibrium 7.1 Equilibrium in Physical Processes 7.2 Equilibrium in Chemical Processes – Dynamic Equilibrium 7.3 Law of Chemical Equilibrium and Equilibrium Constant 7.4 Homogeneous Equilibria 7.5 Heterogeneous Equilibria 7.6 Applications of Equilibrium Constants 7.7 Relationship between Equilibrium Constant K, Reaction Quotient Q and Gibbs Energy G 7.8 Factors Affecting Equilibria 7.9 Ionic Equilibrium in Solution 7.10 Acids, Bases and Salts 7.11 Ionization of Acids and Bases 7.12 Buffer Solutions 7.13 Solubility Equilibria of Sparingly Soluble Salts
Section Name Topic Name 10 The s-Block Elements 10.1 Group 1 Elements: Alkali Metals 10.2 General Characteristics of the Compounds of the Alkali Metals 10.3 Anomalous Properties of Lithium 10.4 Some Important Compounds of Sodium 10.5 Biological Importance of Sodium and Potassium 10.6 Group 2 Elements : Alkaline Earth Metals 10.7 General Characteristics of Compounds of the Alkaline Earth Metals 10.8 Anomalous Behaviour of Beryllium 10.9 Some Important Compounds of Calcium 10.10 Biological Importance of Magnesium and Calcium
Section Name Topic Name 12 Organic Chemistry – Some Basic Principles and Techniques 12.1 General Introduction 12.2 Tetravalence of Carbon: Shapes of Organic Compounds 12.3 Structural Representations of Organic Compounds 12.4 Classification of Organic Compounds 12.5 Nomenclature of Organic Compounds 12.6 Isomerism 12.7 Fundamental Concepts in Organic Reaction Mechanism 12.8 Methods of Purification of Organic Compounds 12.9 Qualitative Analysis of Organic Compounds 12.10 Quantitative Analysis
Class 11th Chemistry Online Class: Elevate Your CBSE Board Success
About Lesson

Water pollution

Water pollution is defined as: “It is the contamination of water with undesirable and harmful substances.”

Environmental Chemistry Class 11th Notes & Solution
Environmental Chemistry

Polluted water has certain characteristics:

  • Bad taste
  • Offensive odour
  • Unpleasant color
  • Unchecked growth of weeds
  • Oil or grease floating on surface

Sources of water pollution

  1. Sewage and domestic waste spread Pathogens:-
  • They form the major part of pollutant. They includebacteria etc. that enter the into water bodies etc. Human excreta usually contain E.coli bacteria and streptococcus bacteria that cause lot of gastrointestinal problems.
  1. Organic wastes:
  • It includes leaves, grass etc. it leads to excessive growth of plants in water bodies.
  • The bacteria act on these waste as they are biodegradable.They consume oxygen dissolved in water and tis concentration of oxygen is very important for aquatic life.
  • Both the bacteria aerobic and anaerobic have harmful effect as anaerobic bacteria breaks down the organic matter and result in the formation of chemicals that give foul smell and are harmful to human health whereas aerobic bacteria degrade the organic matter and lower the concentration of oxygen .
  • Oxygen consumed by microorganism in decomposing the waste present in certain volume of sample of water is called biochemical oxygen demand (BOD) of water.
  1. Chemical pollutants:
  • The lot of metals, chemicalsetc. are disposed in the water bodies and cause lot of harm like metals are very dangerous as we can’t excrete them therefore they can damage kidneys, CNS,liver etc. petroleum and its products also pollute water .
  • The excessive disposal of chemicals in water bodies leads to eutrophication.

Eutrophication is a result of excessive disposal of chemicals that leads to excess growth of algae in water bodies that is water bloom and this water bloom results in oxygen depletion and aquatic life suffers a lot due to this effect.

Radioactive discharge: They enter the water bodies from different sources like nuclear reactions, nuclear tests etc. they emit very harmful radiations.

Polychlorinated biphenyl’s: These are used as fluids in transformers etc. They are resistant to oxidation and when released in atmosphere they cause skin disorders.

International standards of drinking water

There arecertain substances in water which are essential but only up to certain limits.They are as below:


  • Water should be tested for fluoride ion concentration.Its deficiency in water cause harmful diseases like tooth decay etc.The fluoride ion in water help in enamel of teeth much harder by converting hydroxyl-apatite into much harder flour-apatite.


  • The presence of increased concentration of lead can harm kidney, liver and reproductive system.


  • Excessive sulphate can cause laxative effect.


  • The maximum limit of nitrate is 50ppm. Excess nitrate cause methemoglobinemia.
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