Identify compound $Y$ in the following reaction.
$C_2H_5Cl + Y \xrightarrow{\Delta} C_2H_5CN$

Given below are two statements $:$
Statement $(I) :$ $cis-1,2-dichloroethene$ is more polar than $cis-1,2-dibromoethene$.
Statement $(II) :$ Boiling point of $trans-1,2-dibromoethene$ is lower than $cis-1,2-dibromoethene$ but it is more polar than $cis-1,2-dibromoethene$.
In the light of the above statements,choose the most appropriate answer from the options given below $:$

The major product of the following reaction is:

The rate of $\beta$-dehydrohalogenation in the following halides under treatment with a strong base follows the order:

The correct order of the rate of dehydrohalogenation of the following halides in the presence of alcoholic $KOH$ is:

Select the reagent that will yield the greater amount of substitution on reaction with $CH_3CH_2Br$.