Which of the following compounds has the highest boiling point?

Select the correct decreasing order of boiling points of compounds from the following.

What is the correct order of leaving group ability for the following groups?
$I. -OAc$
$II. -OMe$
$III. -OSO_2Me$
$IV. -OSO_2CF_3$

Arrange the following compounds in order of increasing $S_N1$ reaction rate:
$(i)$ $Ph-C(CH_3)_2-Br$
(ii) $CH_3-CH_2-CH(CH_3)-Br$
(iii) $(CH_3)_3C-Br$
(iv) $CH_3-CH_2-CH(CH_3)-Cl$

The order of reactivity of the following compounds towards dilute aqueous $KOH$ in $SN_1$ reaction is
$I$. $CH_3CH_2CH_2CH_2Br$
$II$. $CH_3CH_2CHBrCH_3$
$III$. $(CH_3)_2CHCH_2Br$
$IV$. $(CH_3)_3CBr$

The correct order of $S_{N}1$ reaction rate for the given compounds is: