Q 1920167011.     Arrange the following:
(i) In decreasing order of `pK_b` values :
`C_2H_5NH_2, C_6H_5NHCH_3, (C_2H_5)_2NH` and `C_6H_5NH_2`
(ii) In increasing order of basic strength :
`C_6H_5NH_2, C_6H_5N(CH_3)_2, (C_2H_5)_2 NH` and `CH_3NH_2`
(iii) In increasing order of basic strength :
(a) Aniline, p-nitroaniline and p-toluidine
(b) `C_6H_5NH_2, C_6H_5NHCH_3, C_6H_5CH_2NH_2`
(iv) In decreasing order of basic strength in gas phase :
`C_2H_5NH_2, (C_2H_5)_2NH, (C_2H_5)_3N` and `NH_3`
(v) In increasing order of boiling point :
`C_2H_5OH, (CH_3)_2NH, C_2H_5NH_2`
(vi) In increasing order of solubility in water :
`C_6H_5NH_2, (C_2H_5)_2NH, C_2H_5NH_2`