Which one of the following is formed apart from sodium chloride when chlorine reacts with hot concentrated sodium hydroxide?

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.

When $I_2$ is dissolved in $CCl_4$,the color of the solution formed is .....

The element which can displace three other halogens from their compound is

The correct order of acidic strength is:

Justify,by giving reactions,that among halogens,fluorine is the best oxidant and among hydrohalic compounds,hydroiodic acid is the best reductant.