The order of reactivity of the following alkyl halides for a $S_N2$ reaction is

The formation of alkene from alkyl halide is an example of

Predict the product of the following reaction:
(Image: $A$ chiral carbon attached to a phenyl ring with a para-chloro group,a deuterium atom $(D)$,a hydrogen atom $(H)$,and a chlorine atom (Cl) in a specific stereochemical configuration. The reaction is with $NaI$ in acetone.)

The least reactive alkyl chloride in an $S_N2$ reaction is:

Number of moles of $AgCl$ formed in the following reaction is $X$. Identify $X$ from the given reaction.

$2CHCl_3 + O_2 \xrightarrow{X} 2COCl_2 + 2HCl$. In the above reaction,$X$ stands for: