Write any two methods of preparation of diborane. How does it react with Ammonia .

Explanation

i) Preparation of diborane :
1) Diborane can be prepared by treating boron trifluöride with `LiAlH_(4)` in diethyl ether.
`4BF_(3)+3LiAlH_(4) to 2B_(2)H_(6)+3"LiF"+3AlF_(3)`
2.In the laboratory it is conveniently prepared by the oxidation of sodium boróhydride with iodine.
`2NaBH_(4)+l_(2) to B_(2)H_(6)+2Nal+H_(2)`
3. On large scale it is prepared by reaction of `BF_(3)` with sodiun hydride.
`2BF_(3)+6NaH overset(450K)(to)B_(2)H_(6)+6"NaF"`
ii) Reaction with ammonia :
With ammonia it forms an addition product with asymmetric cleavage. which ion heating forms borazine which is known as inorganic benzene.
`3B_(2)H_(6)+6NH_(3) to 3[BH_(2)(NH_(3))_(2)]^(+)[BH_(4)]^(-)overset("heat")(to)2B_(3)N_(3)H_(6)+12H_(2)`