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| 1. |
Arrange the following in increasing order of their basic strength :C_2 H_5 NH_2. C_6H_5NH_2 ,CH_2and(C_2 H_5) NH |
| Answer» Solution :Due to the +I effect of `C_2 H_5` group, `(C_2 H_3)_2NH` (having two `C_2 H_5` GROUPS attached to N) is more basic than `C_2 H_5 NH_2`. Nowaromatic AMINES, i.e., `C_6 H_5 NH_2` and `C_6 H_5 CH_2 NH_2` are less basic than `C_2 H_5 NH_2`due to -I effect of `C_6H_5 ` group. Out of `C_6 H_5 NH_2`and `C_6 H_5 CH_2 NH_2, C_6 H_5 NH_2` in which `C_6 H_5` group is directly linked to `NH_2` group is less basic than `C_6 H_5 CH_2 NH_2`. This is because thelone PAIR of electrons on nitrogen atoms is delocalized over the BENZENE ring resulting in decrease in electron density on nitrogen. Therefore, the lone pair of electrons on N atom in `C_6 H_5 CH_2 NH_2` is more easily available for protonation than that on the N-atom in `C_6 H_5 NH_2`. Hence, `C_6 H_5 CH_2 NH_2 ` is more basic than `C_6 H_5 NH_2`. Therefore, the correct order of the basic character is :`C_6 H_5 NH_2lt C_6CH_2 NH_2ltC_2H_5NH_2lt (C_2 H_5) NH ` | |