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

Describe simple tests for distinguishing:
p-CH₃COC₆H₄NH₂ and CH₃CONHC₆H₅

Describe simple tests for distinguishing:
C₆H_sNH₃ ⁺Cl^- and p-ClC₆H₄NH₂

Describe simple tests for distinguishing:
CH₃ONHC₆H₅ and C₆H₅CONH₂

Describe simple tests for distinguishing:
(CH₃)₄N⁺OH and (CH₃)₂NCH₂OH