Diborane $\left(\mathrm{B}_{2} \mathrm{H}_{6}\right)$ reacts independently with $\mathrm{O}_{2}$ and $\mathrm{H}_{2} \mathrm{O}$ to produce, respectively:

(B) $\mathrm{B}_{2} \mathrm{O}_{3}$ and $\mathrm{H}_{3} \mathrm{BO}_{3}$

(A) $\mathrm{H}_{3} \mathrm{BO}_{3}$ and $\mathrm{B}_{2} \mathrm{O}_{3}$

(C) $\mathrm{HBO}_{2}$ and $\mathrm{H}_{3} \mathrm{BO}_{3}$

(D) $\mathrm{B}_{2} \mathrm{O}_{3}$ and $\left[\mathrm{BH}_{4}\right]^{-}$

JEE Main · 2019 · 08 Apr 2019 · Shift 1 · p-Block Elements

Diborane

(B_{2} H_{6})

reacts independently with

O_{2}

and

H_{2} O

to produce, respectively:

(A) $H_{3} BO_{3}$ and $B_{2} O_{3}$
(B) $B_{2} O_{3}$ and $H_{3} BO_{3}$ ✓ Correct
(C) $HBO_{2}$ and $H_{3} BO_{3}$
(D) $B_{2} O_{3}$ and $[BH_{4}]^{-}$

Answer: (B)

Solution

Diborane burns in oxygen to boron trioxide,

B_{2} H_{6} + 3 O_{2} \to B_{2} O_{3} + 3 H_{2} O

, while with water it is hydrolysed to boric acid,

B_{2} H_{6} + 6 H_{2} O \to 2 H_{3} B O_{3} + 6 H_{2}

. Taken in the order asked, the products are

B_{2} O_{3}

with oxygen and

H_{3} B O_{3}

with water.

JEE Main · 2019 · 08 Apr 2019 · Shift 1 · Single correct option

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