Chlorine is manufactured by

Explain the electron gain enthalpy values of elements of the $17^{\text{th}}$ group. Give reasons and explain.

Which of the following elements liberates $O_2$ from water?

With reference to aqua regia,choose the correct option$(s)$.
$(1)$ Reaction of gold with aqua regia produces $NO_2$ in the absence of air.
$(2)$ Aqua regia is prepared by mixing conc. $HCl$ and conc. $HNO_3$ in $3:1$ $(v/v)$ ratio.
$(3)$ Reaction of gold with aqua regia produces an anion having $Au$ in $+3$ oxidation state.
$(4)$ The yellow colour of aqua regia is due to the presence of $NOCl$ and $Cl_2$.

Among the following oxoacids,the correct decreasing order of acid strength is?

Which one of the following is present as an active ingredient in bleaching powder for bleaching action?