Saved Bookmarks
| 1. |
Arrange the following in the order of decreasing basic character : (a) (1) CH_3NH_2 (2) (CH_3)_2NH (3) C_6H_5NH_2 NH_3 (b) (1) CH_3NH_2 (2) (CH_3)_2NH (3) CH_3)_3N (4) C_6H_5NH_2 ( c) (1) NH_3 (2) CH_3NH_2 (3) C_6H_5NH_2 (4) (C_6H_5)_2NH (5) (C_6H_5)_3 N (d) (1) C_6H_5NH_2 (2) p-NO_2C_6H_4NH_2 (3) m-NO_2C_6H_4NH_2 (4) p-CH_3OC_6H_4NH_2 ( e) (1) p-Toluidine (2) N,N-Dimethy1-p-toluidine (3) p-Nitroaniline (4) Aniline (f) (1) Methulamine (2) Dimethylamine (3) Aniline (4) N-Methylaniline (g) (1) RCN (2) RNH_2 (3) RN=CHR (h) (1) C_2H_5NH_2 (2) (iso-C_3H_7)_3N (3) CH_3CONH_2 (4) CH_3 overset (Ө) N HN a^(oplus) (i) (1) overset(Ө) N H_2 (2) HC -= C^(Ө) (3) .^(Ө)OH (4) .^(Ө)OR (5) R^(Ө) (6) RCOO^(Ө) (j) (1) H^(Ө) (2) C1^(Ө) (3) NH_2^(Ө) (4) RCOO^(Ө) (5) RO^(Ө) . |
|
Answer» Solution :(a) `2 gt 1 gt 4 gt 3((2) 2^@ amine gt (1) 1^@ amine gt (4)` standard `NH_3 gt (3)` aromatic amine) (b) `2 gt 1 gt 3 gt 4 gt ((2) 2^@ amine gt (1) 1^@ amine gt (3) 3^@ amine gt (4)` aromatic amine) ( c) `2 gt 1 gt 3 gt 4 gt 5 ((2) 1^@ ` amine `gt(1)` Standard `NH_3 gt (3)` Aromatic (amine) `gt (4)` Dipheny1 amine, due to resonance of `L P overline e^, s` on `N` with two benzene rings, basicity decreases `gt (5)` Tripheny1 amine, due resonance of `L P overline e^, s` of `N` with three benzene rings, basicity further decreases, due to nonavailability of `L P overline e^, s` on `N` atom) (d) `4 gt 1 gt 3 gt 2 [(4) (-OMe)` at `p` (`-I` and `+R`, net `overline e` donating) `gt (1)` Standard, aniline ` gt (3) (-I)` effect of `(-NO_2)` at `m-position gt (1) - I and - R` effects of `(-NO_2)` at `p-position`] ( e)  (f) `2 gt 1 gt 4 gt 3 gt [(2) 2^@` amine ` gt (1) 1^@` amine ` gt (4)` Aromatic amine (with `Me` group on `N, + I` effect of `Me` group) `gt (3)` Standard aniline] (G) `2 gt 3 gt 1 [(2) 1^@ R - NH_2(SP^3) gt (3) R-N = CH - R(sp^2) gt (1) R - C -= N(sp)` character] Basicity : `sp^3 gt sp^2` character. (h) `4 gt 1 gt 2 gt 3 (4)` Anion of `1^@` amine `CH_3 - overset Ӫunderset (ddot) N H, L P overline e^, s` density INCREASES `gt (1) 1^@` amine `gt (2) 3^@` amine `gt (3)` amide.  (i)`5 gt 1 gt 2 gt` Convert conjugate base into acid by adding `H^(oplus)`, find the acidic character and then reverse the order after removing `H^(oplus)` ions that would be the order for basic character. Acidity : `underset((6))(RCOOH) gt underset ((3))(H_2)O gt underset (4) ROH gt CH -= underset ((2)) CH gt underset ((1)) NH_3 gt underset ((5)) RH` Basicity : `RCOO^(Ө) lt overset (Ө) OH lt RO^(Ө) lt CH -= C^(Ө) lt overset (Ө) N H_2 lt R^(Ө) (6 lt 3lt 4 lt 2 lt 1 lt 5)`. (j) `(3 gt 1 gt 5 gt 4 gt 2)` Acidity : `underset ((2))HC1 gt underset ((4)) ROOCH gt underset ((5)) ROH gt underset ((1)) (H_2) gt underset ((3)) NH_3` Basicity : `C1^(Ө) lt RCOO^(Ө) lt RO^(Ө) lt H^(Ө) lt NH^(Ө) 2 lt 4 lt 5 lt 1 lt 3` (k)   .
|
|