The rate of $S_N1$ reaction will be faster for which of the following bromides?

$2-$bromopentane is heated with potassium ethoxide in ethanol. The major product is

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

In the presence of light,chloroform is slowly oxidised by air to form:

Which of the two stereoisomers of $4-t-$butylcyclohexyl iodide $(^{127}I^-)$ will undergo $S_N2$ substitution with $^{128}I^-$ faster,and why?

The reaction of $4-methylcyclohexyl$ halide with $OH^-$ via the $S_N2$ mechanism produces $A$. Identify $A$.