MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: R

There are no items in this cart.
Continue Shopping
Menu
Eeya Choudhary Grade: Upto college level
        

How is NaOH or KOH manufactured?

8 years ago

Answers : (1)

askIITIians Expert
21 Points
										








 


 

The normal oxides of the alkali metals react with water forming the hydroxides, which are the strongest bases known. The special methods of manufacture of hydroxides are as follows:


 

 


 

1.         Gossage’s process or Sodalime Process : Slaked lime (Calcium Hydroxide) and dilute Sodium Carbonate solution are reacted in large tanks when the following reaction occurs.


 

 


 

                        Ca(OH)2 + Na2CO3 >< CaCO3¯ + 2NaOH


 

 


 

            Although this reaction is reversible, most of the sodium carbonate is converted to the hydroxide because calcium carbonate (insoluble) precipitates out. The sodium hydroxide is decanted from the sludge and concentrated (or evaporated) to dryness.


 

 


 

2.         Electrolysis of NaCI


 

This process is carried out either in Nelson cell (Diaphragm cell) or Castner – Kellner cell (mercury cathode process).


 

 


 

            In Nelson cell following reaction occur


 

 


 

                        NaCI >< Na+ + CI


 

 


 

            At cathode      Na+ + e ® Na


 

 


 

                                    2Na + 2H2O ® 2NaOH + H2­


 

 


 

            At anode         2CI – 2e ® CI2­


 

 


 

In Castener – Kellner cell the sodium ions Na+ discharge on cathode (Hg) and form sodium amalgam; which reacts with water to form sodium hydroxide :


 

 


 

                        NaCI >< Na+ + CI


 

 


 

            At cathode      Na+ + e ® Na


 

 


 

                                    Na + Hg ® Na(Hg)


 

 


 

                                    2Na(Hg) + 2H2O ® 2NaOH + H2 + 2Hg­


 

 


 

            At anode         2CI – 2e ® CI2­


 

 


 

The sodium hydroxide so obtained may contain the impurities of NaCI, Na2SO4 and Na2CO3. To obtain pure sodium hydroxide impure sample of NaOH is dissolved in alcohol and solution is filtered. The filterate on evaporation gives the pure flakes of NaOH.

8 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies
  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details

Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers
To Win!!! Click Here for details