The major ingredient $(51 \%)$ in Portland cement is

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

Consider the following sequence of reaction

$$ 2 \mathrm{CH}_3 \mathrm{Cl}+\mathrm{Si} \xrightarrow[573 \mathrm{~K}]{\mathrm{Cu}} X \xrightarrow{\mathrm{H}_2 \mathrm{O}} Y \xrightarrow{\text { Polymerisation }} Z $$

The repeating structural unit in Z is

Which of the following is not the common component of photochemical smog?