MCQ
$H_3BO_3$ is
- ✓Monobasic and weak Lewis acid
- BMonobasic and weak Bronsted acid
- CMonobasic and strong Lewis acid
- DTribasic and weak Bronsted acid
✓
Answer
Correct option: A.
Monobasic and weak Lewis acid
a
Central boron atom in $\mathrm{H}_{3} \mathrm{BO}_{3}$ is electron deficient, therefore it accepts a pair of electrons, hence it is weak Lewis acid. There is no d-orbital of suitable energy in boron atom.
Central boron atom in $\mathrm{H}_{3} \mathrm{BO}_{3}$ is electron deficient, therefore it accepts a pair of electrons, hence it is weak Lewis acid. There is no d-orbital of suitable energy in boron atom.
So, it can accommodate only one additional electron pair in its outermost shell. Thus, $\mathrm{H}_{3} \mathrm{BO}_{3}$ is monobasic weak Lewis acid.
$\underset{\text { Base }}{\mathrm{H}_{2} \mathrm{O}}$+$\underset{\text { Acid }}{\mathrm{B}(\mathrm{OH})_{3}} \longrightarrow\left[\mathrm{B}(\mathrm{OH})_{4}\right]^{-}+\mathrm{H}^{+}$
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