Methylation of Diborane (B2H6) replace only four hydrogen why ?

Methylation of Doborane:

(1) In diborane two boron atoms and four terminal hydrogen atoms lie in one plane. While two bridge hydogen atoms (encircled ) lie smmetrically above and below the plane.

(2) Total valence electrons in B₂H₆ is 12(6 from boron 3x2) and 6 from six hydrogen atoms) and there are two B-H-B (3C-2e) bridge bonds and four B-H (2C-2e) terminal bonds.

(3) Bond energy of B-H-B bond is 441 kj per mole which greater than bond energy B-H bond (341Kj per mole) hence methylation of diborane no more than four hydrogen.

(4) In above reaction it is clearly reveal that none of the bridge hydrogen in B₂H₆  has been replaced by –CH₃ .ie in this reaction both the bridge bond remaine undissociate.

Related Questions: 

(1) Why aqueous solution of AlCl3 is acidic in nature ?

(2) What happen when aq AlCl3 react with Acid or Base?

(3) Although anhydrous aluminium chloride is covalent but its aqueous solution is ionic in nature. Why?

(4) Why BF3 do not exist as dimer?. Explain.

(5) Why B-F bond length in BF3 is shorter (130 pm) than B-F bond Iength in BF4- (143 pm)?. Explain.

(6) B-F bond length in BF3 is shorter than B-F bond length in (BF4)- why?

(7) When B2H6 is allowed to react with following Lewis bases, then how may given Lewis base form adduct through symmetrical Cleavage of B2H6.

(8) What is product of reaction between diborane (B2H6) and ammmonia (NH3)?

(9) Why methylation of Diborane (B2H6) replace four hydrogen only ?

(10) What is Use of Boric Acid?

(11) What is use of Orthoboric acids?

(12) What is basicity of "Boric acid" ?

(13) Why Boric acid exist in solid state ?

(14) What is structure of solid Ortho Boric acid ?

(15) What is effect of heat on Borax?

(16) What is the structure of trimetaboric acid and trimetaborate ion?

(17) What is the Sodium per borate ,give the structure and its uses?

(18) Why aqueous solution of borax reacts with two moles of acids ?

(19) What is the molecular formula of Borax ?

(20) Why Boric acid become strong acid in the presence of cis 1,2-diol or 1,3-diol ?

(21) Why Borazine is more reactive than benzene towards Electrophic Aromatic substitution reactions ?

(22) Why Borazine (B3N3H6) is also known as inorganic benzene ?.

(23) Four-center two-electron bond (4C-2e Bond): Structure of AlCl3:

(24) What is the difference between the structure of AlCl3 and diborane?

What is the Sodium per borate ,give the structure and its uses?

Sodium per borate (NaBO₃.H₂O) (more correctly sodium dioxoborate peroxohydrate) is prepared from borax by treatment with NaOH to convert it to sodium borate (NaBO₂) and further reaction with hydrogen peroxide.

Structure of sodium per borate:

What is Use of Boric Acid?

 Boric acid commonly known as TANKAN AMLA and use as Anti diaphoretic agent (anti sweating), Anti infective and also non-irritant agent. It is use in skin cream which provides nourishment and luster to the skin and also keeps soft, smooth and healthy Skin.

Boric acid also used in manufacturing of ENAMELS and Glazes for pottery and as disinfectants in medicine.

Why aqueous solution of AlCl3 is acidic in nature ?

Aluminium forms covalent compound with chloride because lionization enthalpy (∆iH= +5137 kJ/mole) of Aluminium is very high due to small size and chlorine is unable to convert  Al into Al⁺³ ions. 

However, when anhydrous AlCl₃ (which is covalent in character) is dissolved in water, it undergoes hydration as follow:  

AI₂CI₆ + H₂O -->2[Al(H₂O)₆]⁺³ +(∆H)  

Hydration of anhydrous Aluminium chloride is highly exothermic in nature. The hydration enthalpy is more than ionisation enthalpy of aluminium.This hydration enthalpy removes all the three valence electrons of the aluminium leading to the formation of Al³⁺ more easly.This AI³⁺ is hydrated with water and form a complex ion. Thus in water Al exist as [Al(H₂O)₆]⁺³. so aqueous AlCl3 form Hexahydrated complex salt.

Related Questions: 

(1) Although anhydrous aluminium chloride is covalent but its aqueous solution is ionic in nature. Why?

(2) Why Ga has small size than Al exceptionally

(3) Why aqueous solution of borax reacts with two moles of acids ?

(4) What is structure of solid Ortho Boric acid ?

(5) What is the structure of trimetaboric acid and trimetaborate ion?  

(6) Why Borazine is more reactive than benzene towards Electrophic Aromatic substitution reactions ?

(7) Why Borazine (B3N3H6) is also known as inorganic benzene ?.

(8) Why B-F bond length in BF3 is shorter (130 pm) than B-F bond Iength in BF4- (143 pm)?. Explain.

(9) Why B-F do not exist as dimer?. Explain.

(10) Although anhydrous aluminium chloride is covalent but its aqueous solution is ionic in nature. Why?

(11) Why Boric acid become strong acid in the presence of cis 1,2-diol or 1,3-diol ?

(12) Four-center two-electron bond (4C-2e Bond): Structure of AlCl3:

(13) What is the molecular formula of Borax ?

(14) What is the difference between the structure of AlCl3 and diborane?

What is Hypovalent species or compounds ?

The compounds or ions which doesn't follow octet rule inspite of that contains less than eight electrons and also stable called Hypovalent species.

For examples BeF₂,BF₃, CH₄⁺, NF₂⁺, B₂H₆, Be₂Cl₄ etc

Hypovalent species may act as Lewis acid always.