Which of the following undergoes $S_N1$ reaction at the fastest rate?

Differentiate between the $S_N2$ and $S_N1$ mechanisms of alkyl halides.

Identify the correct order for the given property for the following compounds. Choose the correct answer from the options given below:
$(A)$ Boiling Point: $CH_3CH_2Cl < CH_3CH_2CH_2Cl < CH_3CH_2CH_2CH_2Cl$
$(B)$ Density: $CH_3CH_2Br < CH_3CH_2Cl < CH_3CH_2I$
$(C)$ Boiling Point: $CH_3CH_2Br < (CH_3)_2CHBr < (CH_3)_3CBr$
$(D)$ Density: $CH_3CH(I)Br < CH_3CH_2CH_2Br < CH_3CH(Br)Cl$
$(E)$ Boiling Point: $CH_3CH_2CH_2CH_2Cl > (CH_3)_2CHCH_2Cl > (CH_3)_3CCl$

Identify $A$ and $B$ in the following reaction:
$C_2H_5Cl \xrightarrow{A} C_2H_5OH \xleftarrow{B} C_2H_5Cl$

Phosgene is formed slowly from which one of the following on exposure to air and sunlight?

The formation of alkene from alkyl halide is an example of