When $MnO_2$ and $H_2SO_4$ are added to a salt $(A)$,the greenish yellow gas liberated indicates that salt $(A)$ is:

What is the product obtained in the reaction of $HgCl_2$ and $Hg(CN)_2$?

Two statements are given below.
Statement $I$: $SnF_4$ and $PbF_4$ are ionic in nature.
Statement $II$: $GeCl_2$ is more stable than $GeCl_4$.
The correct answer is:

Silica is soluble in which of the following?

Carbon can form $p\pi-p\pi$ bond with which kind of elements?

Observe the oxides $CO, B_2O_3, SiO_2, CO_2, Al_2O_3, PbO_2, Tl_2O_3$. The number of acidic oxides in the list is: