JEE Main 2022 · 24 Jun · Shift 1 · Chemistry Q70

ChemistrySingle correct+4 / -1Question 70 of 90

Identify the correct statement for $\mathrm{B_2H_6}$ from those given below.

(A) In $\mathrm{B_2H_6}$ , all B-H bonds are equivalent.

(B) In $\mathrm{B_2H_6}$ , there are four 3-centre-2-electron bonds.

(D) $\mathrm{B_2H_6}$ can be synthesized from both $\mathrm{BF_3}$ and $\mathrm{NaBH_4}$ .

(E) $\mathrm{B_2H_6}$ is a planar molecule.

Choose the most appropriate answer from the options given below :

(A) and (E) only

(B), (C) and (E) only

Answer and worked solution

Official answer: C

Check each statement.

(A) False: four terminal B-H bonds differ from the four bridging B-H-B bonds.
(B) False: there are two 3-centre-2-electron (banana) bonds.
(C) True: boron is electron deficient, so diborane acts as a Lewis acid.
(D) True: $\mathrm{4BF_3+3NaBH_4\rightarrow2B_2H_6+3NaBF_4}$ uses both.
(E) False: the terminal H atoms lie in one plane and the bridging H atoms lie above and below it.

(C) and (D).

(C)

Topics:Boranes Group 13

JEE Main 2022 · 24 Jun · Shift 1, Chemistry question 70