Haloalkanes and Haloarenes

List the following compounds in order of decreasing reactivity toward $${CH}_{3}O$$ in an $${S}_{N}2$$ reaction carried out in $${CH}_{3}OH$$; $${CH}_{3}F$$, $${CH}_{3}Cl$$, $${CH}_{3}Br$$, $${CH}_{3}I$$, $${CH}_{3}O{SO}_{2}{CF}_{3}$$, $$_{  }^{ 14 }{ { CH }_{ 3 } }OH$$
The maximum  rate of $$Sn2$$ is :
Write the stereochemical products formed in the given elimination reaction.
The reaction conditions leading to the best yield of $$C_{2}H_{5}Cl$$ are:
Assertion: Chloroform gives chloropicrin with $$HNO_{3}$$ vapour.
Reason: Chloropicrin is used as an insecticide.