Question

Identify the correct statements regarding structure of diborane

• A. There are two bridging hydrogen atoms.
• B. Each boron atom forms four bonds
• C. All hydrogen atoms are not in same plane
• D. Each boron atom is in $s{p}^3$ hybridized state

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A There are two bridging hydrogen atoms.
B Each boron atom forms four bonds
C All hydrogen atoms are not in same plane
D Each boron atom is in $s{p}^3$ hybridized state

a) $B{H}_3$ dimerizes to give diborane $\left(B_2{H}_6\right)$, in which two hydrogen atoms are bridged and four hydrogen atoms are terminal.
b) On dimerization, each boron atom is bonded with two terminal and two bridged hydrigen atoms i.e each has a steric number of 4. Hence both borons in $B_2{H}_6$ are $s{p}^3$ hybridised.
c) In $B_2{H}_6$, two borons and four terminal hydrogens lie in same plane, while bridged hydrogen atoms lie above and below the plane.
d)The dimerized $B{H}_3$ has four sigma bonds. Hence steric number of $B$ is four. So each boron in diborane is $s{p}^3$ hybridized.