In ${\mathrm{S}}_{\mathrm{N}}1$ reaction, the racemisation takes place. It is due to:

Rank the following compounds in the order of increasing ${\mathrm{E}}_2$ reaction rate with alcoholic $\mathrm{KOH}$.

$50\%$ of the reagent is used for dehydrohalogenation of $6.45 \mathrm{g} {\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Cl}$. What will be the weight of the main product obtained?
[Atomic mass of $\mathrm{H}, \mathrm{C}$ and $\mathrm{Cl}$ are $1, 12$ and $35.5 \mathrm{g}/\mathrm{mole}$, respectively].

Consider the following bromides

(A) 

(B) 

(C) 

The correct, order of ${\mathrm{S}}_{\mathrm{N}}1$ reactivity is

Arrange the following in decreasing order of stability of their transition state during elimination by a strong base:

(I) 

(II) 

(III) 

If 

what will be the major product of the following reaction

 major product.