One of the hydrolysed products of the following compound does not react with the silica of a glass vessel.

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 $Cl_2$.

Which element from the following combines with hydrogen to form a compound having the lowest acidic strength?

Which of the following is the strongest reducing agent?

Industrially,bromine is obtained from $........$.

Which halogen oxidizes water at room temperature but does not undergo disproportionation into it?