Which of the following has the maximum tendency to form polyanions?

Identify the method used to obtain $SO_2$ gas in industry.

In the preparation of $H_2SO_4$ by the Contact Process,why is $SO_3$ not absorbed directly in water to form $H_2SO_4$?

Which of the following statements is incorrect for $H_2SO_4$?

How many total statements are correct in the following?
$(i)$ $SO_2$ - antichlor,preservative
$(ii)$ $O_3$ - Disinfectant
$(iii)$ $Cl_2$ - Antiseptic
$(iv)$ $O_2$ - used in oxy-acetylene welding
$(v)$ $PH_3$ - used in smoke screens
$(vi)$ $HNO_3$ - Pickling of stainless steel

Which of the following dissociates to give ${H^{+}}$ most easily?