Why does fluorine not show disproportionation reaction?

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

Phosphorus reacts with $SO_2Cl_2$ to form $PCl_5$ and $X$. At $723 \ K$,$HCl$ gas reacts with $O_2$ in the presence of $CuCl_2$ to form water and $Y$. $Y$ reacts with $X$ in water to form two acids $A$ and $B$. What are $A$ and $B$ respectively?

Chlorine is allowed to react with an excess of ammonia. In this reaction, $1$ mole of chlorine can oxidize '$Z$' moles of $NH_3$. The value of '$Z$' is:

$A$ solid $A$ which has photographic effect reacts with the solution of a sodium salt $B$ to give a pale yellow precipitate $C$. The sodium salt $B$ on heating with concentrated $H_2SO_4$ gives brown vapours. Identify $A$,$B$,and $C$.

Assertion : Fluorine exists only in $-1$ oxidation state.
Reason : Fluorine has $2s^2 2p^5$ configuration.