Acids

      Acids

*Acids are those compounds 

  which gives Hydrogen ions (H+ ion) in aqueous solutions.

For example-

       HCl --------> H+    +  Cl`

       (aq)            (aq)       (aq)

* Acids are those compounds which makes hydronium ions in aqueous solutions.

For example-

          HCl --------> H+    +  Cl`

       (aq)            (aq)       (aq)

H+  +   H2O ------->  H3O+

                           (Hydronium ion)

* Acids are those compounds which is reacts with bases and form salts and water.

For example-

NaOH  +  HCl -------> NaCl +H2O

(Base)     (Acid)      (Salt)   (Water)

* Acids are those compounds which are sour  in taste.

  For example- citric acid , lactic acid etc.

*Organic acids and mineral acids-

(1)Organic acids-  The acids present in plant materials and animals are called organic acids.

 For example- Acetic acid, formic acid etc.

(2)Inorganic acids-  The acids prepared from the minerals of the earth are called mineral acids.

 For example- HCl,  H2SO4 , HNO3 etc.

*Strong acids and weak acids-

(1) Strong acids-   The acids which gives maximum number of the Hydrogen ions in the aqueous solutions are called strong acids. 

All the mineral acids are strong acids.( Exception Carbonic acid)

For example- HCl,  H2SO4 , HNO3 etc.

 (2)Weak acids-    The acids which gives minimum number of the Hydrogen ions in the aqueous solutions are called weak acids. 

All the Organic acids are weak acids.

For example- citric acid, lactic acid etc.

*Concentrated acids and Dilute acids-

(1) Concentrated acids-  A concentrated acid is one which contains the minimum possible amount of water in it.

(2) Dilute acids-  A dilute acid is one which contains much more of water in it.

Properties of acids-

(1) Acids have a sour taste.

(2) Acids turn blue litmus to red.

(3) Acid solutions conduct electricity.

(4) Acids reacts with metals to form hydrogen gas.

    Zn  +  H2SO4 ------> ZnSO4 + H2

(5) Acids reacts with metal carbonates and metal hydrogen carbonates to form carbon dioxide ( CO2) gas.

  Na2CO3 + 2HCl ------> 2NaCl + CO2 + H2O 

(6) Acids reacts with bases to form salts and water.

  NaOH + HCl ------> NaCl + H2O 

(7) Acids reacts with metal oxides to form salts and water.

  CuO + 2HCl ------> CuCl2 + H2O

(8) Acids have corrosive nature.