An oxide of an element is a gas and dissolves in water to give an acidic solution. The element belongs to:

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

Explain the origin and sources of group $14$ elements.

Which of the following is not correct?

$A$ 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.

The gas produced by the passage of air over hot coke is