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NEET Chemistry Notes p-Block Elements -Some Important Compounds of Group 13 Elements

NEET Chemistry Notes p-Block Elements -Some Important Compounds of Group 13 Elements

Some Important Compounds of Group 13 Elements

Some Important Compounds of Group 13 Elements

Some of important compounds of group 13 elements or boron family are given below :

Diborane, (B2H6 )

Diborane is a colourless, highly toxic gas with a boiling point of 180 K. Diborane catches fire spontaneously upon exposure to air.
NEET Chemistry Notes p-Block Elements -Some Important Compounds of Group 13 Elements 1
Borazine

Borazine (B3N3H6) is known as “inorganic benzene” in view of its ring structure with alternative BH and groups. However, at high temperature, inorganic graphite (BN)X is obtained instead of borazine.

Structure of diborane
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Terminal halogens (Ha are bonded by 2c – 2e (two centred two electrons) bonding and bridge hydrogens (Hb) are bonded by 3c – 2e (three centred held by two electrons) bonding. This type of bonding is also known as banana bonding. Orbital Sturcture of (B2H6 )
Due to banana bonding, B2H6 complete its electron
deficiency and obtain ethane like structure and hybridisation of(B2H6 ) becomes sp .
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It is used as a catalyst in polymerisation process, for welding torch, as reducing agent in organic reactions etc.

Borax (Na2B407 10H2O)
[Sodium Tetra Borate Decahydrate]

It is the most important compound of boron. It is white crystalline solid.
Borax dissolves in water to give an alkaline solution.
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Boric Acjd (H3BO3)

Boric acid is soft white crystalline solid, soapy to touch and less soluble in cold water.
Boric acid is a weak monobasic acid. It is not a protonic acid but acts as a Lewis acid.
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Structure of boric acid shows that it has a layer structure in which planar BO3 units are joined by H-bonds.
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Uses

It is used as an antiseptic, eye wash, as food preservative, in glass industry and in pottery.

Aluminium Chloride

  • Anhydrous aluminium chloride is a white deliquescent solid which fumes in air. .Its vapour density corresponds to the formula Al2Cl6.
  •  It is covalent and soluble in organic solvents.
  •  Structure of AlCl3
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Uses

Anhydrous AlCl3 is used as a reagent in Friedel-Crafts reaction. In manufacture of drugs, dyes, perfumes. In cracking of high boiling fractions of petroleum to form gasoline.

Alums

  •  These are double sulphates having composition M2S04.M’ (S04)3 .24H20 (M = monovalent basic radicals such as Na+, K+ etc., and M’ = trivalent basic radicals such as Al3+, Cr3+ etc.)
  • Potash alums;K2S04 .A12(S04)3 . 24H20
  •  Sodium alums; Na2S04 .A12(S04)3 .24H20
  •  Ferric alums; (NH4)2S04. Fe2(S04)3 .24H20
  •  On heating, alum swells up leaving behind a porous mass, called burnt alum.

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