What is the product formed when $Ethyl \ bromide$ reacts with alcoholic $Silver \ nitrite$ $(AgNO_2)$?

Given below are two statements:
Statement $I$: The conversion $CH_3-CH_2-CH_2-CH_2-Cl \xrightarrow{OH^{-}} CH_3-CH_2-CH_2-CH_2-OH + Cl^{-}$ proceeds well in a less polar medium.
Statement $II$: The conversion $(CH_3)_3C-Cl \xrightarrow{OH^{-}} (CH_3)_3C-OH + Cl^{-}$ proceeds well in a more polar medium.
In the light of the above statements,choose the correct answer from the options given below.

Haloalkanes react with $KCN$ to form alkyl cyanides as the main product,while $AgCN$ forms isocyanides as the chief product. Explain.

Toluene reacts with $Cl_2$ in the presence of .............. to form benzyl chloride.

$C_2H_5I$ $\xrightarrow{\text{alc. } KOH} X$ $\xrightarrow{Br_2} Y$ $\xrightarrow{KCN} Z$; $Z = \dots$

What is the correct order of nucleophilicity for an $S_N2$ reaction?