The large difference between the melting and boiling points of oxygen and sulphur may be explained on the basis of

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 statements is incorrect?

Excess of $PCl_{5}$ reacts with conc $H_{2}SO_{4}$ to give:

Below are two statements. One is labeled as Assertion $(A)$ and the other as Reason $(R):$
Assertion $(A):$ $H_2Te$ is more acidic than $H_2S$.
Reason $(R):$ The bond dissociation enthalpy of $H_2Te$ is less than that of $H_2S$.
In the context of the above statements,choose the correct answer from the following options:

Sodium thiosulphate is prepared by: