In esterification,the reactivity of alcohols is:

Which one of the following is a secondary alcohol?

$CH_3-CH(OH)-CH_3$ $\xrightarrow{PBr_3} X$ $\xrightarrow{Mg/\text{ether}} Y$ $\xrightarrow{H_2O/H^+} \text{The final product is}$

Which of the following compounds will form a hydrocarbon on reaction with a Grignard reagent?

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:

The order of reactivity of the following alcohols with halogen acids is . . . . . .
$(A)$ $CH_3-CH_2-CH_2-OH$
$(B)$ $CH_3-CH_2-CH(OH)-CH_3$
$(C)$ $CH_3-CH_2-C(CH_3)_2-OH$