Which isomer of $C_4H_9OH$ has the highest boiling point?

Which among the following compounds has the highest melting point?

An optically active alcohol of formula $C_9H_{12}O_2$ produced the following compound when refluxed with $KMnO_4$. What is the structure of $(A)$? The original compound showed these properties also:
$\mathop {C_9H_{12}O_2}\limits_{(A)} \xrightarrow{Na} H_2 \text{ liberated}$
$\mathop {C_9H_{12}O_2}\limits_{(A)} \xrightarrow{Br_2} \text{ no rapid reaction}$
$\mathop {C_9H_{12}O_2}\limits_{(A)} \xrightarrow[{cool}]{CrO_3 / H^{+}} C_9H_8O_3$

Which is the best reagent to convert isopropyl alcohol to isopropyl bromide?
$CH_3-CH(OH)-CH_3 \xrightarrow{?} CH_3-CH(Br)-CH_3$

Identify the compound having the highest solubility in water from the following:

The boiling point of glycerol is higher than that of propanal because of: