${\mathrm{S}}_{\mathrm{N}}2$ mechanism proceeds through intervention of:

What is the major product obtained in the following reaction?

Match List $\mathrm{I}$ (Reaction) with List $\mathrm{II}$ (Type of reaction) and select the correct answer using the code given below the lists:

	List I		List II
P		1	${\mathrm{S}}_{\mathrm{N}}1$
Q		2	${\mathrm{S}}_{\mathrm{N}}2$
R		3	${\mathrm{E}}_1$
S		4	${\mathrm{E}}_2$

Indicate whether each of the following compound is '$\text{E}$' or '$\text{Z}$'.

The number of chiral carbon atoms in the compound $\mathrm{W}, \mathrm{X} , \mathrm{Y}$ and $\mathrm{Z}$ respectively would be

How many chiral centres are present in the following compounds?