Silicon has a strong tendency to form polymers like silicones. The chain length of silicone polymers can be controlled by adding:

$A$ compound $A$ is used in paints instead of salts of lead. Compound $A$ is obtained when a white compound $B$ is strongly heated. The compound $B$ is insoluble in water but dissolves in $NaOH$ solution,forming a solution of compound $C$. The compound $A$ on heating with coke gives a volatile metal $D$ and a gas $E$ which burns with a blue flame. Identify the possible species $D$ and $C$ respectively.

When ferric oxide reacts with $NaOH$,the product formed is

Number of oxygen atoms present in the chemical formula of fuming sulphuric acid is . . . . .

Given below are the atomic numbers of some group $14$ elements. The atomic number of the element with the lowest melting point is:

The most basic oxide of elements in group $14$ of the periodic table is