By means of calcium chloride,which of the following can be dried?

What is the final product $(IV)$ in the following reaction sequence? $CH_3-CH(OH)-CH_3$ $\xrightarrow{PBr_3} I$ $\xrightarrow{Mg/ether} II$ $\xrightarrow{\text{Ethylene oxide}} III$ $\xrightarrow{H_2O} IV$

When $3, 3-$dimethyl$-2-$butanol is heated with ${H_2SO_4}$,the major product obtained is:

The reaction of Lucas reagent is fast with

Ethylene glycol,on oxidation with periodic acid $(HIO_4)$,gives:

Which is most viscous?