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

Choose the correct statement about allotropes of carbon.

I. Graphite has layered structure.

II. Buckminster fullerene is not aromatic in nature.

III. The distance between two adjacent layers in graphite is 141.5 pm .

IV. The hybridisation of carbon in graphite and Buckminster fullerene is same.