Acids, Bases, & salts chapter 2. Science

-

On the basis of their chemical properties all the compounds can be classified into 3 categories.
1. Acids.             2.Bases.            3. Salts.

ACIDS:

Acids are substances having a sour taste.
Many fruits are sour because they contains acids. 
Examples: vinegar, tomatoes, lemon juice etc.

• Organic Acids ( naturally occurring):

The Acids produced by plants & animals (except hydrochloric acid).
Ex.  Ethanoic acid.
 

• Mineral Acids:

The Acids formed from minerals present in the earth's crust.
Ex.  Nitric Acid.

         Name of Acid              Source

Plants.      Citric Acid                orange & lemon
                Tartaric Acid.          Tamarind & grapes
              Oxalic Acid.                  Tomatoes
              Methanoic Acid.           Nettle sting

Animal     Lactic Acid             sour milk
                Methanoic Acid       Ant sting
                   Stearic Acid           Animal fats 
                 Uric Acid.                  Urine.

BASES:

Bases are the substances which taste bitter and feel slippery to the skin.
Ex. Caustic Acid, washing soda, baking soda.

Some bases are soluble in water. These soluble bases are known as Alkalies.
Ex.  Sodium hydroxide, pottasium hydroxide.

SALTS:

Salts are the compounds formed from acids and bases. 
Ex. When hydrochloric acid combines with sodium hydroxide, a salt ( sodium chloride) is obtained.

  HCl  +.  NaOH  ➡.    NaCl + H2O

Indicators to test Acids & Bases:

Some substances change their colour on addition of an aqueous solution of an acid or a base. These called Acid - Base indicators.

Three Indicators are:
  • LITMUS:. Extract from lichen tree.
  ( Natural Indicator)
  • PHENOLPHTHALEIN
  • METHYL ORANGE
   ( They both are synthetic Indicators)

Litmus paper: Blue litmus solution or red litmus solution, thin paper strips soaked in these solutions. 
• If blue litmus solution changes red, then the substance is acidic. 
• If red litmus solution changes to blue, then the substance is basic.

OLFACTORY INDICATORS:
There are certain substances whose odour changes in an acidic or a basic solution.











Comments

Post a Comment

Popular posts from this blog

Class 10 Science (Biology) Heredity and Evolution

-
Image
~ INTRODUCTION  In the last chapter you have studied how organisms reproduce to produce new individuals. The offsprings produced as a result of reproduction are similar to their parents as well as other individuals of the species. For example, man resembles man in body shape size etc. Similarly dogs resemble dogs,  cows resemble cows, and so on. Similarly the plant obtain from the seed of a mustard plant is similar to its parent. The offspring plant is similar to other mustard plants as well. But how is it that the offsprings are similar to other members of the species as well as to Parents. All this happens because of the presence of genes in parent/parents which are transferred to the next generation via  gametes or other means. These genes transfer the biological information of parents to offsprings which gives rise to various characteristics in the offspring thereby making them similar to parents or other members of species.  These differences in characteristics ...
Read more

National anthem, National song, National Bird , National animal, National game, national flower, first' president, first prime minister, Republic day , independence day.

-
Image
1. Who composes the national anthem? Ans. Rabindranath Tagore. 2. Who composes the national song? Ans. Bankim Chandra Chatterjee. 3. Which is national flower? Ans. Lotus. 4. Which national Animal? Ans. Tiger 🐅. 5. Which is national game? Ans. Hockey 🏒. 6.which is national song?  Ans. Vande maataram. 7. Which is national bird? Ans. Peacock 🦚. 8. Which is national fruit? Ans. Mango 🥭. 9. Who was first prime minister of India? Ans. Pandit Jawaharlal Nehru. 10. Who was first president of India? Ans. Dr. Rajendra Prasad. 11. When was Independence day celebrated? Ans. 15 August  every year.  12. When was Republic day celebrated? Ans. 26 January every year.
Read more

Chapter 7 control & coordination class 10th

-
Image
  Stimuli The changes in the environment or environmental factors to which the organisms respond and react are called stimuli. Coordination The working together of the various organs of an organism in a systematic manner so as to produce a proper reaction to the stimulus, us called coordination. System functions by the release of chemical messengers -- the hormones and is called endocrine system and the other works by the Conduction of nerve impulses like the Conduction of an electric current and is called nervous system. ANIMALS-- NERVOUS SYSTEM The system by which controls and coordinates all the activities of various parts in response to external and internal stimuli by the Conduction of nerve impulses is called nervous system. Sense organs Name of receptors     stimulus    location Photoreceptors             light             Eyes Phonoreceptors          ...
Read more