Which halide will be most reactive towards $SN^2$ reaction?

The rate of $S_N2$ reaction will be negligible in:

Which among the following alkyl halides gives more than one product upon dehydrohalogenation?

The reduction of chloroform with $Zn$ and $HCl$ (alc.) gives ..........

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 correct order of the rate of the reaction for the following reaction with respect to nucleophiles is: $CH_{3}Br + Nu^{\ominus} \longrightarrow CH_{3}Nu + Br^{\ominus}$