Which of the following types of hybridization occurs in diborane $(B_2H_6)$?

The structure of diborane contains:

Which one of the following statements is not correct?

What is the molecular formula of borazole?

Which of the following processes is used to prepare borazine?

Boron trifluoride on reaction with lithium aluminium hydride in ether gives $LiF$, $AlF_3$ and $X$. $X$ on reaction with $NH_3$ gives $Y$. $Y$ on further heating gives a compound $Z$. The number of $\sigma$-bonds and $\pi$-bonds in $Z$ are $x$ and $y$ respectively. $(x+y)$ is equal to