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Photosynthesis in higher plants

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Class 10 Class 12

Arrange the following in the order of decreasing basicity:
C2H5NH2, iso-(C3H7)3N, CH3CONH2, CH3NH-Na+


CH3NH-Na > C2H5NH2 > (iso-C3H7)3N > CH3CONH2
CH3NH- is the conjugate base of the very weak acid CH3NH2 and therefore is the strongest base. The three bulky isopropyl groups on cause steric strain, but with an unshared electron pair on N, the strain is partially relieved by increasing the normal C—N—C bond angle (109°) to about 112°. If the unshared electron pair forms a bond to H, as in R3NH+, relief of strain by angle expansion is prevented. 3° Amines, therefore, resist forming the fourth bond and suffers a decrease in basicity. In CH3CONH2, the N atom is weakly basic because its electron pair can be delocalised to O of the CH3CO— group by extended straight pi bonding.


Arrange the following in the order of decreasing basicity:
C6H3NH2, p-NO2C6H4NH2, m-NO2.C6H4NH2, p-CH3 OC6H4NH2.


p-CH3OC6H4NH2 > C6H5NH2 > m-NO2.C6H4. NH2 > p-NO2.C6H4.NH2-NO2 group in m-position weakens the base due to inductive effect while in o- and p- positions it weakens the base due to -I effect and extended straight pi bonding. 


Arrange the following in the order of decreasing basicity:
NH3, CH3NH2, C6H5NH2 (C6H5)2NH.


CH3NH2 > NH> C6H5NH2 > (C6H5)2NH > (C6H5)3N.

Arrange the following in the order of decreasing basicity:
Methyl amine, dimethyl amine, aniline, N-methyl aniline.


Dimethylamine > methylamine > N-methyl aniline > aniline.

Arrange the following in the order of decreasing basicity:
p-Toluidine, N, N-dimethyl-p-toluidine, p-nitro aniline, aniline.


p-Toluidine > aniline > p-nitroaniline > N, N-dimethyi-p-toluidine.