Starting from borax, how would you obtain :
(a) Boric acid
(b) Boron trioxide
( c) Boron
(d) Bororn nitride
( e) Boron trichloride.

Explanation

(a) By the acidification of borax
`Na_(2)B_(4)O_(7) + H_(2)SO_(4)+5H_(2)O rarr Na_(2)SO_(4) + 4H_(3)BO_(3)`
(b) By the acidification of borax,
`Na_(2) B_(4) O_(7) +H_(2)SO_(4) _ 5H_(2)O rarr Na_(2)SO_(4) + underset("Boric acid")(4H_(3) BO_(3))`
following by strong heating of boric acid,
`2H_(3)BO_(3) overset(Delta)rarr underset("Boron oxide")(B_(2) O_(3)) + 3H_(2) O`
( c) By the acidification of borax,
`Na_(2) B_(4)O_(7) + H_(2) SO_(4) + 5H_(2) O rarr Na_(2)SO_(4) + 4H_(3) BO_(3)`
followed by strong heating of boric acid,
`2H_(3) BO_(3) overset(Delta)rarr underset("Boron oxide")(B_(2)O_(3)) + 3H_(2) O`
and then reduction of boron oxide by strong electropositive metal, `Mg`.
(d) `Na_(2) B_(4)O_(7) +NH_(4)Cl rarr underset("Boron nitrate") (2BN) + B_(2) O_(3) + 2NaCl + 4H_(2) O`
( e) `B_(2)O_(3) + 3C + 3Cl_(2) rarr 2BCl_(3) + 3CO`.