Halogens: Sources and Importances

 Fluorine

Sources of fluorine: Fluorspar (CaF₂), Cryolite (Na₃AlF₆), Fluorapetite CaF₂,3Ca₃(PO₄)₂

Why did fluorine call super halogen?
Answer; 1) Highest electronegative element, 2) absence of "d" in atomic structure, 3) F—F bond energy is very less, 4) very small size of Fluorine ion.

Highest oxidizing agent

Reaction with water >>
3H₂O+3F₂= 6HF+O₃
HF and Ozone gas produced.

A compound produced by fluorine: 

Freon (Any of several nonflammable refrigerants), Teflon (polytetrafluoroethylene), Sodium monofluorophosphate (used in fluoride toothpaste to prevent tooth decay), sodium fluoroacetate FCH₂COONa (used in rat killers), Magnesium fluoride MgF₂ (used to make a glass of spectacles)

Chlorine 

Sources of Chlorine: Salt (NaCl), Silvain (KCl), Carnalite (KCl.MgCl₂.6H₂O), Horn silver (AgCl)

Chlorine water: At normal temperature chlorine is dissolved in water and produces a lite yellow coloured solution, that's called chlorine water.
H₂O+Cl₂= HCl+HOCl

Why is chlorine water always kept in black coloured bottles?
In presence of sunlight chlorine water or HOCl analyses itself into HCl and nascent oxygen [O], to avoid this decomposition chlorine water is kept in black coloured bottles.

How did bleaching powder prepare from chlorine?
At 40°C temperature chlorine gas reacted with dried quick lime [Ca(OH)₂] and produced bleaching powder or calcium chlorohypochlorite [Ca(OCl)Cl].

Uses of Chlorine:
1) Used to produce bleaching powder, gammaxene, DDT, Polyvinyl Chloride (PVC), 2) uses to make poisonous gas Phosgene and Mustard gas. 3) in preparation of chloroform (CHCl₃) which is acts as an anaesthetic.

Bromine

Uses of Bromine:
Potassium bromide (KBr): used to make sleeping medicine
Silver bromide (AgBr): used in photography
Bromoacetone (BrCH₂COCH₃): used to make tear gas
Methyl bromide (CH₃Br): used as a pesticide

Iodine

Sources of Iodine:
Seawater and kelp or seaweed.

Iodine can directly react with other halogens and form Interhalogen compounds.
Like: IF₇, IF₅, ICl₃, ICl, IBr e.t.c.

Uses of Iodine:
Tincture of iodine
Iodoform (CHI₃):a yellow crystalline compound, formerly used as a mild antiseptic and pesticide.
Silver Iodide (AgI): used in photographic film and to produce artificial rain
Nesler reactant: used to identify ammonia
Indothyrine: A compound of iodine used as an injection to treat goitre.