Bushra, the order of basicity or basic nature for the given set of compounds is as follows:-

Aniline < Ammonia < Ethanamine

The basis for this order is the fact that basicity depends on the ability of a compound to donate a pair of electrons or the ability to abstract a proton. The tendency to donate a pair of electrons increases in ethanamine from that of ammonia due to presence of electron releasing CH3CH2 group which is electron releasing due to +I- Effect (Inductive effect), whereas the tendency to donate a pair of electrons decreases in case of Aniline due to electron withdrawing Phenyl group which withdraws the electron density away from Nitrogen of -NH2 group through mostly the Resonance effect which withdraws the electron density away from Nitrogen and hence the lone pair of electron on N is less available for donation. In case of Ammonia, there is no Inductive or Resonance effect, so its basic nature remains in between that of Ethanamine and Aniline.

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