Question

Orthoboric acid $\left(H_{3}B{O}_3\right)$ and metaboric acid $\left(HB{O}_2\right)$ differ in respect of

• A. basicity
• B. structure
• C. melting point
• D. none of the above

Answer 1

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

The correct options are
A basicity
B structure
C melting point

A) The $pKa$ values of orthoboric acid are $9.24,12.4,13.3$, while the $pKa$ value of metaboric acid is $9.236$. Thus, they differ in acidity/basicity.
B) The molecular formula of orthoboric acid is $H_{3}B{O}_3$, while the molecular formula of metaboric acid is $H_3{B}_3{O}_6$ or $HB{O}_2$.
C) The melting point of metaboric acid is about ${236}^{o}C$, while the melting point of orthoboric acid is ${170.9}^{o}C$.