Class = 10 (Chemistry) Science Acids,Bases and Salts

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 (ii) Mineral Acids : The acids formed from minerals present in the earth's crust are known as mineral acids. Nitric acid was the first mineral acid. Later on, sulphuric acid and hydrochloric acid were discovered. These mineral acids much stronger than ethanoic acid and allow more chemical reactions to take place. Many chemical discoveries are based on the use of these acids. 

In everyday life, we used a number of acids. Hydrochloric acid is used in cleaning kitchen sinks and sanitary wares. It is worth to note that hydrochloric acid is produced in our stomach also. Sulphuric acid is used in batteries of inverters, cars, buses, trucks, etc. Nitric acid is used by goldsmiths for cleaning gold and silver ornaments. Given in table 2.2 are the important mineral acids with their chemical formulae.

From the above discussion, we find that one element is common to all the acids, which is hydrogen. Thus, we can say that presence of hydrogen is essential for a substance to act as an acid. 


~ BASES 

Bases are the substances which taste bitter and feel slippery to the skin. Some of the familiar bases are caustic soda (sodium hydroxide), washing soda (sodium carbonate), baking soda (sodium hydrogen carbonate), caustic Potash (potassium Hydroxide), lime (calcium hydroxide) and milk of magnesia (magnesium Hydroxide). All Metal oxides and hydroxides (except Ammonium hydroxide, which is not a metallic hydroxide) are bases.

• Some bases are soluble in water.
• These soluble bases are known as alkalies.
• Sodium hydroxide and potassium hydroxide are examples of alkalies which are used in laboratories.

~ SALTS 

Salts are the compounds formed from acids and bases. For example when hydrochloric acid combines with Sodium Hydroxide, a salt (called sodium chloride) is obtained,


A few more examples of the salts are copper sulphate, calcium carbonate, silver nitrate, ammonium sulphate,etc. 

Salts which have taste similar to that of common salt are termed as salty. However, some of the salts have very unpleasant taste and even may be poisonous. Thus, it is very dangerous to taste any chemical substance.

We shall now study how to test whether the given substance is an acid or a base without tasting it.

       To be continued......

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