(a) (i) (I) The $ ext{pK}_ ext{b}$ value of aniline is higher than that of methylamine. Explain why. (II) Arrange the following compounds in decreasing order of their basic strength in the gaseous phase : $ ext{NH}_3$, $( ext{C}_2 ext{H}_5)_2 ext{NH}$, $( ext{C}_2 ext{H}_5)_3 ext{N}$, $ ext{C}_2 ext{H}_5 ext{NH}_2$ (III) What is Hinsberg's reagent ? Mention its one use. (ii) How will you convert the following : (I) Nitrobenzene to Benzenediazonium chloride ? (II) Iodomethane to Ethanamine ?