The laboratory test 'tailing of mercury' is used to identify:

Which of the following compounds contains an $S - S$ bond?

Which of the following are peroxo acids of sulphur?

Elements of group $16$,except $Po$,are known as chalcogens because .........

In the manufacture of sulphuric acid by the contact process,the Tyndall box is used to

Statement $(A)$ Sulphur vapour is paramagnetic. Statement $(B)$ Reaction of dil. $HCl$ with finely divided iron forms $FeCl_3$ and $H_2$ gas. The correct answer is