Which of the following statements is not correct?

Boron trifluoride on reaction with lithium aluminium hydride in ether gives $\mathrm{LiF}^{\circ} \mathrm{AlF}_3$ and $X . X$ on reaction with $\mathrm{NH}_3$ 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

Sulphur dioxide on reaction with chlorine in the presence of charcoal gives compound $(A)$. This on reaction with white phosphorus gives $\mathrm{SO}_2$ and compound $(B)$. The correct statement about ' $B$ ' is

Diborane on hydrolysis gives a compound $X$. The correct statement about $X$ are

I. It is a tribasic acid

II. It is a weak monobasic acid

III. It has a layer structure

IV. It is highly soluble in water