Which of the following represents the correct graph for $S_N2$ reaction?

Which of the following reacts most rapidly with ethanol?

Which of the following will react with a halogen acid at the slowest rate?

Identify $Z$ in the following series of reactions:

Predict the major product for the following $E2$ elimination reaction:

Arrange the following alkyl halides in the increasing order of their reactivity towards nucleophilic substitution reaction:
$(I)$ $CH_3CH_2CH(Cl)CH_3$
$(II)$ $CH_2=CHCH(Br)CH_3$
$(III)$ $CH_2=CHCH(Cl)CH_3$
$(IV)$ $CH_3CH=C(Br)CH_3$