Home | | Chemistry | | Chemistry | Isolation, Physical, Chemical Properties, Uses Of Fluorine

Chapter: 11th 12th std standard Class Organic Inorganic Physical Chemistry Higher secondary school College Notes

Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail

Isolation, Physical, Chemical Properties, Uses Of Fluorine

Isolation, Physical, Chemical Properties, Uses Of Fluorine
Symbol - F Atomic number -9 Period Number :2 Valency -1 Atomic mass-19 Group Number : 17 Dennis' Method:Fluorine does not occur free in nature. It occurs in the combined form. Dennis' Method: This was devised by Dennis, Veeder and Rochow in 1931.

 

ISOLATION OF FLUORINE

Symbol - F Atomic number -9                  Period Number   :2

Valency -1 Atomic mass-19    Group Number      : 17

Fluorine does not occur free in nature. It occurs in the combined form. 

Dennis' Method: This was devised by Dennis, Veeder and Rochow in 1931.

In this fluorine is prepared by the electrolysis of fused sodium or potassium hydrogen fluoride (perfectly dry) Electrolysis is carried out between graphite electrodes in a V-shaped electrically heated copper tube. The ends of the tube are covered with copper caps into which the graphite electrodes are fixed with bakelite cement. The copper tube is thickly lagged to prevent loss of heat.

KHF2 KF + HF

HF H+ + F

2H+ + 2e- H(At cathode)

2F - - 2e- F2 (At anode)

Fluorine liberated at the anode is passed through the U-tube containing

sodium fluoride. Thisremovesthe hydrogen fluoride vapourscomingwithfluorine.

NaF +HF NaHF2



Physical Properties

1.    Fluorine is a gas and has pale greenish yellow colour.

2.    It has extremely pungent and penetrating odour. 3. It is heavier than air.

Chemical Properties

Fluorine is the most active member of halogen family.

1. Action with Hydrogen: Hydrogen explodes violently in fluorine even in the dark.

 

H2 + F2  2HF

2. Action with non-metals: Non-metals like carbon, silicon and phosphorus burn in fluorine forming fluorides.

 

C + 2F2  CF4

Tetra fluoromethane

 

Si + 2F2  SiF4

Silicon tetrafluoride

 

2P + 5F2  2PF5

Phosphorus pentafluoride

 

3.    Action with metals: It reacts with metals forming corresponding fluorides.

2Ag + F2  2AgF

2Al + 3F2  2AlF3

4. Formation of Interhalogen compounds: It forms a variety of inter halogen compounds with other halogens.

 

Br2 + 3F2  2Br F3

I2 + 5F2  2 IF5

Uses

1. Fluorine is used in the manufacture of a series of compounds known as

freons. These non-toxic, non-combustible and volatile liquids are used as refrigerants in refrigerators, deep freezers and air conditioners. The most

common, freon is known as dichlorodifluoro methane CF2 Cl2.

2. CaF2 is used as flux in metallurgy.

3. NaF is used as a preservative to prevent fermentation and also for preventing dental cavities.

4. SF6 is used as an insulating material in high voltage equipment.

5. Teflon is used as container to store hydrofluoric acid.

6. UF6 is used in the separation of U235 from U238.

 

Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail


Copyright © 2018-2020 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.