(i)           Acetone undergoes clemmensen reduction in presence of zinc amalgam and conc.HCl to give propane.
 
(ii)          Acetone reacts with semicarbazide to form semicarbazone.
 
(iii)        Acetone reduces to form tertiary alcohol in the presence of Grignard reagent.
 
(b) Due to extensive hydrogen bonding, carboxylic acid has the highest boiling points an among the given compound. Alcohols, with a smaller number of the hydrogen bond, have a lesser boiling point. Aldehydes have least boiling point due to the absence of hydrogen bonding.
Hence the order of boiling point is:
CH3-CHO