Alkyl halide is converted into alkyl isocyanide by reaction with

Arrange the following compounds in decreasing order of reactivity for nucleophilic substitution reaction:
$(I)$ $CH_3-CH_2-OSO_2CF_3$
$(II)$ $CH_3-CH_2-OTs$
$(III)$ $CH_3-CH(OH)-CH_3$
$(IV)$ $C_6H_5-CH(OH)-CH_3$

The conversion of ethyl bromide to ethyl iodide using sodium iodide and dry acetone is known as:

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.)

Consider the given reaction: $CH_3-CH=CH-CH_2-OH \xrightarrow[S_N1]{HBr} [P]$. In the given reaction,the product $[P]$ is:

Identify the structure of the major product in the following reaction:
$Ph-CH(Br)-CH(Br)-CHO \xrightarrow[\Delta]{K_2CO_3} ?$