Which pair of halogens does not undergo a disproportionation reaction with water?

The sublimate formed during the process of sublimation of $Hg_2Cl_2$ with $NaCl$ is .........

Which one of the following halogens liberates oxygen when passed through hot concentrated $KOH$ solution?

Arrange $CCl_4$,$AlCl_3$,$PCl_5$,and $SiCl_4$ in the increasing order of their ease of hydrolysis.

As the atomic number of halogens increases,the halogens

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A :$ Fluorine forms one oxoacid.
Reason $R :$ Fluorine has the smallest size amongst all halogens and is highly electronegative.
In the light of the above statements,choose the most appropriate answer from the options given below.