Identify the product formed when tertiary butyl bromide reacts with alcoholic $NH_3$ solution?

Which of the following will react faster through the $S_N 1$ mechanism?

Which of the following reactions is an example of a nucleophilic substitution reaction?

Which of the following nucleophiles will show minimum reactivity towards $S_N2$ reaction:

An unknown compound $A$ has the molecular formula $C_5H_9Cl$. It does not react with $Br_2 / CCl_4$. When treated with a strong base,it gives a compound $B$ with the molecular formula $C_5H_8$,which reacts with $Br_2 / CCl_4$. Ozonolysis of $B$ followed by treatment with dimethyl sulfide gives a compound with the molecular formula $C_5H_8O_2$. What is the structure of $A$?

Among the given halides,which one will give the same product in both $S_{N^1}$ and $S_{N^2}$ reactions?
$(I) \ CH_3-CH(CH_3)-CH_2-CH(Br)-CH_3$
$(II) \ \text{2-methylcyclohexyl chloride}$
$(III) \ \text{Chlorocyclohexane}$
$(IV) \ CH_3-CH(Br)-CH_2-CH_3$