Question

Select the correct statements about diborane:

• A. $B_2{H}_6$ has three centred two electron bond
• B. Each boron atom lies in $s{p}^3$ hyrid state
• C. Terminal $H...B...H$ bond angle is ${120}^{\circ }$
• D. All hydrogen in $B_2{H}_6$ lie in the same plane

Answer 1

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

Terminal $H...B...H$ bond angle is ${120}^{\circ }$

Three centered two electron bond is present is diborane, $B_2{H}_6$.
It has two 3- centre 2 electron bond, each one consisting of the two boron atoms and a hydrogen atom sharing two electrons.

Boron is $s{p}^3$ hybridised, as 4 orbitals of each boron atom will be hybridised to accomodate the electrons.
Since, each boron atom is $s{p}^3$ hybridised So, terminal $H-B-H$ bond angle is nearly ${120}^{\circ }$
All hydrogen is $B_2{H}_6$ are not lie in the same. Two boron atoms and the four terminal hydrogen atoms of the molecule are in the same plane and the bridging hydrogen atoms lie above and below this plane.
Thus, this statement is incorrect.