Answer to Question #194662 in Organic Chemistry for Joshua

Question

With reasons, arrange the following: ( 4mks)

(i) In increasing order of basic strength: C6H5NH2, C6H5N(CH3)2, (C2H5)2 NH and CH3NH2.

(ii) In increasing order of boiling point: C2H5OH, (CH3)2NH, C2H5NH2

Answer 1

(C6H5​)2NH<C6H5NH2<C6H5N(CH3​)2​<CH3​NH2

​

Due to the −I effect of C6

​H5 group, the electron density on N-atom C6

​H5​−NH2​ is lower than that on the N-atom (C6

​H5​)2NH . But in case of C6​H5​N(CH3​)2​, two CH3

​ group attached with N atom which increases the electron density on N-atom and in CH3​−NH3

​ only +I effect of methyl group increases the basicity of the compound

(CH3)2 NH < C2H5NH2 < C2H5OH

Note: Stronger H-bonding, more b.p more solubility Alcohol > Amine In amines on H attached to N takes part in H-bond.