Cyclopentanol on reaction with $NaH$ followed by $CS_{2}$ and $CH_{3}I$ produces a/an

Which of the following substances gives a yellow precipitate with $I_2$ and alkali?

Which of the following alcohols will yield alkyl chloride at once on reaction with concentrated $HCl$ and $ZnCl_2$ at room temperature?

Isopropyl alcohol heated at $300\,^{\circ}C$ with a copper catalyst forms:

How many structural isomers of alcohols with the formula $C_4H_9OH$ are possible if all the carbons are in a straight chain?

Consider the following alcohols:
$(I)$ $C_6H_5CH_2OH$
$(II)$ $O_2N-C_6H_4-CH_2OH$ (para-nitro)
$(III)$ $CH_3O-C_6H_4-CH_2OH$ (para-methoxy)
$(IV)$ $Br-C_6H_4-CH_2OH$ (para-bromo)
The order of decreasing reactivities of these alcohols towards nucleophilic substitution with $HBr$ is: