Describe the shapes of $BF $$_{3}$ and $BH _{4}^{-}$. Assign the hybridisation of boron in these species.

Which of the following sublimes on heating?

A neutral molecule $XF_3$ has a zero dipole moment. The element $X$ is most likely

Which of the following statements about ${H_3}B{O_3}$ is not correct

Identify the compounds $A, X$ and $Z$ in the following reactions : 

$A + 2HCl + 5{H_2}O \to 2NaCl + X$

$X\xrightarrow[{370\,K}]{\Delta }HB{O_2}\xrightarrow[{ > 370\,K}]{\Delta }Z$