Question

Which of the following is not true regarding the nature of halides of boron?

• A. Boron trihalides are covalent.
• B. Boron trihalides are planar triangular with $s{p}^2$ hybridisation.
• C. Boron trihalides act as Lewis acids.
• D. Boron trihalides cannot be hydrolysed easily.

Answer 1

The correct option is D Boron trihalides cannot be hydrolysed easily.

Boron trihalides like $B{F}_3$ are covalent in nature. These are forming with $s{p}^2$ hybridization in the shape of triangular planar. All trihalides are strong in acidic nature, as Lewis acids. They react with water to form boric acid.

The sequence for the Lewis acidity is $B{F}_3<BC{l}_3<BB{r}_3$, where $BB{r}_3$ is the strongest Lewis acid. But these trihalides can be easily hydrolyzed except $B{F}_3$ due to the highly stable nature of $B{F}_3$.

Thus option D is correct.