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Q.
What is the nature of the bond between $B$ and $O$ in $(C_{2}H_{5})_{2}OBH_{3}$ ?
AFMCAFMC 2012
Solution:
In $\left( C _{2} H _{3}\right)_{5} OBH _{3}$ coordinate bond a formed in between $B$ and $O$.
$\left(C _{2} H _{5}\right)_{2} O \longrightarrow BH _{3}$
$\left( C _{2} H _{5}\right)_{2}$ gives one lone pair of electron pair $BH _{3}$. So, it is called electron pair donor and $BH _{3}$ is called electron pair acceptor.