p-Block Elements-I - Result Question 2
####2. Diborane $\left(B _2 H _6\right)$ reacts independently with $O _2$ and $H _2 O$ to produce, respectively.
(2019 Main, 8 April I)
(a) $B _2 O _3$ and $H _3 BO _3$
(b) $B _2 O _3$ and $\left[BH _4\right]^{-}$
(c) $H _3 BO _3$ and $B _2 O _3$
(d) $HBO _2$ and $H _3 BO _3$
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Answer:
Correct Answer: 2. (a)
Solution:
- Diborane $\left(B _2 H _6\right)$ reacts independently with $O _2$ and $H _2 O$ to produce $B _2 O _3$ and $H _3 BO _3$ respectively. Diborane is a colourless, highly toxic gas, having boiling point $180 K$. Because of its inflammable nature, it catches fire spontaneously when exposed to air and burns in oxygen releasing an enormous amount of energy as:
$$ B _2 H _6+3 O _2 \longrightarrow B _2 O _3+3 H _2 O+1976 kJ / mol $$
It gets hydrolysed readily to give boric acid.
$$ \underset{\text { Borane }}{B _2 H _6}+6 H _2 O \longrightarrow \underset{\text { Orthoboric acid }}{2 H _3 BO _3}+\underset{\text { Dihydrogen }}{6 H _2 \uparrow} $$
