Consider the following sequence of reactions:
`B_(2)O_(3)+CaF_(2)+H_(2)SO_(4) to (A) + (B) + H_(2)O`
`(A)+ LiAlH_(4) to ( C) (g) +(D) + LiF`
`( C)+H_(2)O underset(Delta)to (D) +H_(2) uarr`
`(D) + Na_(2)CO_(3) to (E) + NaBO_(2) + CO_(2) uarr`
(E)`+NH_(4)Cl to (F) +B_(2)O_(3) + NaCl+ H_(2)O`
What is the empirical mass of compound `(F)`?

Answer

B

Explanation

`B_(2)O_(3)+CaF_(2)+H_(2)SO_(4) tounderset((A))(2BF_(3)uarr)+underset((B))(3CaSO_(4))+3H_(2)O`
`4BF_(3)+3LiAlH_(4) to underset(( C))(2B_(2)H_(6)uarr)+underset((D))(3AIF_(3))+3LiF`
`B_(2)H_(6)+H_(2)Ooverset(Delta)to H_(3)BO_(3)+H_(2)uarr`
`overset((C))(H_(3)BO_(3))+Na_(2)CO_(3)to overset((D))(Na_(2)B_(4)O_(7))+NaBO_(2)+CO_(2)`
`underset((E))(Na_(2)B_(4)O_(7))+2NH_(4)Cl to underset((F))overset((E))(2(BN)_(x))+B_(2)O_(3)+2NaCl+4H_(2)O`
Empirical formula mass of `BN=10.8+14=24.8~~25`