Boron halides are usually Lewis acids in nature. This is due to:

State the uses of aluminium and copper.

Which of the following on hydrolysis produces diborane $(B_2H_6)$?

When $B_2H_6$ reacts with excess $NH_3$ at a very high temperature $(> 200 \, ^\circ C)$,the product formed is:

In which of the following,a salt of the type $KMO_2$ is obtained?

$A$ nonmetallic element of group $13$,used in making bulletproof vests,is an extremely hard solid of black colour. It can exist in many allotropic forms and has an unusually high melting point. Its trifluoride acts as a Lewis acid towards ammonia. The element exhibits a maximum covalence of four. Identify the element and write the reaction of its trifluoride with ammonia. Explain why the trifluoride acts as a Lewis acid.