What is obtained when nitric acid reacts with chloroform?

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

What is the product formed by the reaction of $2-$methylpropene with $HBr$ in the presence of peroxide?

$C_6H_5CH_2Cl + KCN(aq.) \to X + Y$
Compounds $X$ and $Y$ are

When chloroform is exposed to air and sunlight,it gives ...... .

Among the given halides,which one will give the same product in both $S_{N^1}$ and $S_{N^2}$ reactions?
$(I) \ CH_3-CH(CH_3)-CH_2-CH(Br)-CH_3$
$(II) \ \text{2-methylcyclohexyl chloride}$
$(III) \ \text{Chlorocyclohexane}$
$(IV) \ CH_3-CH(Br)-CH_2-CH_3$