Which among the following compounds has the highest boiling point?

Explain elimination reactions of alkyl halides.
or
Explain dehydrohalogenation ($\beta$-elimination) of alkyl halides.

Assertion $(A)$: $S_N1$ hydrolysis of optically active $2-$bromooctane results in the formation of $(\pm)-$octan$-2-$ol.
Reason $(R)$: The reaction proceeds through a planar carbocation which can be attacked by the nucleophile from either side.
The correct answer is

From each of the following pairs,select the compound that will react faster with sodium iodide in acetone:
Pair-$A$: $(1) \, 2-$Chloropropane,$(2) \, 2-$Bromopropane
Pair-$B$: $(3) \, 1-$Bromobutane,$(4) \, 2-$Bromobutane

Which of the following compounds will not give a precipitate with $AgNO_3$?

In the given pairs of reactions,in which pair is the second reaction more reactive than the first toward $S_{N}2$ reaction?