Which of the following undergoes nucleophilic substitution exclusively by $S_N1$ mechanism?

The $E_2$ product of the following reaction will be?

Consider the following reaction,
$C_2H_5Cl + AgCN \xrightarrow{EtOH / H_2O} \underline{X} \text{ (major)}$
Which one of the following statements is true for $\underline{X}$?
$(I)$ It gives propionic acid on hydrolysis
$(II)$ It has an ester functional group
$(III)$ It has a nitrogen linked to ethyl carbon
$(IV)$ It has a cyanide group

What are the products obtained from the following reaction?

Acetone is mixed with bleaching powder to give

Which of the following can be used as the halide component for Friedel-Crafts reaction?