The reaction of chloroform with concentrated $HNO_3$ yields ........

Among the following organic halides,arrange them in the increasing order of their dehydrohalogenation reactions in the presence of alcoholic $KOH$:
$(A)$ $CH_3-CH_2-Br$
$(B)$ $CH_3-CH_2-CH_2-Br$
$(C)$ $CH_3-CH(Br)-CH_3$
$(D)$ $(CH_3)_3-CBr$

The structure of product $(A)$ is:

In the following reaction $C_6H_5CH_2Br \xrightarrow{1. Mg, \text{ ether } \atop 2. H_3O^{+}} X$,the product $X$ is

Which of the following haloalkanes would undergo $S_{N}2$ reaction at the fastest rate?

Which of the following is an example of an $S_N2$ reaction?