Amines are usually formed from amides, imides, halides, nitro compounds, etc. They exhibit hydrogen bonding which influences their physical properties. In alkyl amines, a combination of electron releasing, steric and H-bonding factors influence the stability of the substituted ammonium cations in protic polar solvents and thus affect the basic nature of amines. Alkyl amines are found to be stronger bases than ammonia. Amines being basic in nature, react with acids to form salts. Aryldiazonium salts, undergo replacement of the diazonium group with a variety of nucleophiles to produce aryl halides, cyanides, phenols and arenes. Answer the following questions : (a) How can you convert the following ? (i) Ethanoic acid to methanamine (ii) Propanenitrile to 1-aminopropane (b) Why is $\text{pK}_\text{b}$ value of aniline more than that of methylamine ? (c) (i) Arrange the following in increasing order of their basic strength in aqueous solution : $\text{CH}_3-\text{NH}_2$, $(\text{CH}_3)_2\text{NH}$, $(\text{CH}_3)_3\text{N}$ OR (c) (ii) Give the structures of A and B in the following reaction : $\text{C}_6\text{H}_5\text{NO}_2 \xrightarrow{\text{Fe/HCl}} \text{A} \xrightarrow[273\text{ K}]{\text{HNO}_2} \text{B}$