Which of the following is product $A$ in the above reaction?

Which among the following will have the highest density?

The product $(Y)$ is:

The reaction of an alkyl halide with $Mg$ in dry ether produces ..... as the product.

Arrange the following organic halides in the correct order of reactivity towards $S_{N}2$ displacement:
$(P) \ (CH_3)_2C(Br)CH_2CH_3$
$(Q) \ BrCH_2(CH_2)_3CH_3$
$(R) \ CH_3CH(Br)(CH_2)_2CH_3$

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 $:$