Students guide - by Manoj Verma

  Unit :-14          Acid ,Base and Salt Acid : A substance which gives hydrogen ions (H + ) when dissolved in water is called acid. For example : hydrochloric acid Sulphuric acid Nitric acid Carbonic acid Types of acid : They are 2 types : 1)Organic acid : The acid which are obtained from living being( i.e. plants and animals   ) are called organic acid . .For example : Carbonic acid , Acetic acid, Citric acid   etc. 2.)Inorganic acid :The acid which are obtained from minerals are called inorganic acid . .For example : Hydrochloric acid Sulphuric acid Nitric acid   Properties Physical properties i)It possess sour test . ii)Strong acid are highly corrosive in nature so,they are not tested . iii)Some acid are poisonous i.e. Hydrogen cyanide is most poisonous acid . iv)Some acid are solid i.e . Citric acid and some are liquid i.e. Hydrochloric acid. v)Acid change blue litmus paper into red ,methyl orange into pink, phenolphthalein   into colour

               Unit :-15   Some Useful Chemicals 1.)Water : Water : A substance composed of the chemical elements hydrogen and oxygen is called water .It is found  in gaseous, liquid, and solid states . It is one of the most plentiful and essential of compounds.  it has the important ability to dissolve many other substances Physical properties of water i)It is a colourless, odourless and tasteless liquid ii).It is an excellent solvent. iii)The boiling point of water is 100 0 C and freezing of water is 0 0 C . iv)At 4 0 C water has maximum density and minimum volume . Chemical properties of water 1)Amphoteric nature : Water can act as both acid and base, which means that it is amphoteric   in nature. 2. 2)Reaction with alkali metal : When water   react with alkali metal   oxide and hydrogen gas is obtained Uses of water : It is used for following purpose : 1) Domestic uses of water : It is used for drinking, bathing, cooking food and washing dishes, clothes, f

Unit :- 24  Environment and Sustainable (Digo) Development Environment : Environment is the totality of physical and biological world where living being and non living being things exist .Living being get air, water, food, habitat, etc . from the environment . Biodiversity : The degree of variation of life on the earth on the basis of their number ,type, genes ,ecosystem etc is known as biodiversity .It refers to the total number of organism and their degree of variation . Importance of biodiversity : i)To develop the fundamental aspect . ii)To reduce the risk of local and global climate change . iii)To control the pollutants . iv)To protect areas from soil erosion ,floods,and other harmful weather conditions. Types of biodiversity :Biodiversity is mainly 3 types : 1.)Ecosystem diversity : The diversity in ecological system due to variation in climate and geographical condition is called ecosystem diversity .In Nepal various types of aquatic and terrestrial ecosystem

  Unit :-23     Environmental     degradation and its Conservation Environmental pollution : The degradation of one or more components due to natural and artificial causes is called environmental pollution . Environmental management: The proper management of causative factors of environmental pollution to bring improvement in environmental conservation is called environmental management . Types of pollution: There are    mainly   5 types of pollution: A.)Air pollution: The condition of degrading of natural quality of air due to mixing of different pollutants in atmosphere is called air pollution. Sources of  or causes air pollution: They are 2 types : i.)Natural sources : The sources which are originated directly from nature are called natural sources. For example :Volcanic eruption, forest fire, soil erosion, vapoure   released by plants .etc. ii.)Artificial sources : The sources which are not naturally made but caused due to human activities are called artificial