Identify the incorrect statement about silica $(SiO_2)$.

Silicon is the main constituent of

In the dimer of phosphorus pentaoxide $(P_4O_{10})$,what is the correct order of the number of $P-O-P$,$P=O$,and $P-P$ bonds?

Mention the catenation order for group $14$ elements.

Match the following:
| List-$I$ | List-$II$ |
| :--- | :--- |
| $A$. Carbon black | $I$. Electrodes in batteries |
| $B$. Graphite | $II$. Extraction of metals |
| $C$. Diamond | $III$. Abrasive |
| $D$. Activated charcoal | $IV$. Filler in automobile tyres |
| | $V$. Air conditioning system |

Explain the following reactions:
$(a)$ Silicon is heated with methyl chloride at high temperature in the presence of copper.
$(b)$ Silicon dioxide is treated with hydrogen fluoride.
$(c)$ $CO$ is heated with $ZnO$.
$(d)$ Hydrated alumina is treated with aqueous $NaOH$ solution.