The correct formula of borax is $Na_2[B_4O_5(OH)_4] \cdot 8H_2O$. If the formula is represented as $Na_2[B_4O_5(OH)_x] \cdot yH_2O$, then the sum of $x$ and $y$ is:

Give important trends and anomalous properties of boron.

Diborane reacts with ammonia under different conditions to give a variety of products. Which one among the following is not formed in these reactions?

Which element of group $13$ does not show the group valency in its compounds?

$A$ 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.

The material used in the nuclear industry as protective shields and control rods is