All the boron trihalides except `BI_(3)` may be prepared by direction between the elements. Boron trihalides consist of trigonal-planar `BX_(3)` molecules. Unlike the halides of the other elements in the group they are monomeric in the gas, liquid and solid states, `BF_(3)` and `BCl_(3)` are gases, `BBr_(3)` is a volatile liquid and `BI_(3)` is a solid. Boron trihalides are Lewis acids because they form simple Lewis complexes with suitable bases, as in the reaction:
`BF_(3)(g)+NH_(3)(g)toF_(3)B-NH_(3)(s)`
However, boron chlorides, bromides and iodides are susceptible (sensitive) to protolysis by mild proton sources such as water, alcohols and even amines, for example `BCl_(3)` undergoes rapid hydrolysis:
`BCl_(3)(g)+3H_(2)O(l)toB(OH)_(3)(aq)+3HCl (aq)`
It is supposed that the first step in the above reaction is the formation of the complex `Cl_(3)B larr OH_(2)` which then eliminates `HCl` and reacts with water.
Which of the following reactions is incorrect ?
A. `BF_(3)(g) +F^(-)(aq)rarr [BF_(4)]^(-)(aq)`
B. `BCl_(3)(g)+3EtOH(l)toB(OEt)_(3)(l)+3HCl (g)`
C. `BBr_(3)(l)+F_(3)BN(CH_(3))_(3)(s)toBF_(3) (g)+Br_(3)BN(CH_(3))_(3)(s)`
D. `BCl_(3) (g)+2 C_(5)H_(5)N (l)toCl_(3)B(C_(5)H_(5)N)_(2) (s)`
