Which Aniline Derivative Is More Basic: Ortho or Para Substituted?

[atavistic]

Homework Statement

Which isomer is more basic in the following pairs:

o-methyl aniline or p-methyl aniline

o-chloro aniline or p - chloro aniline

o - chloro aniline or o-floro aniline

o-nitro aniline or p-nitro aniline

 

[Spirochete]

I'd think about this in terms of factors that either stabilize or destabilize the positive charge on nitrogen after it accepts a proton. For example if the charge is destabilized more it means the conjugate base must be weaker.