Isopropyl alcohol on oxidation gives

Which of the following can work as a dehydrating agent for alcohols?

Which one has the highest boiling point?

Which of the following is most soluble in water?

Which of the following will have the highest viscosity?

Optically active $3-$methylpent$-1-$en$-3-$ol loses its optical activity after standing in water containing a few drops of acid,mainly due to the formation of: