Effect of steric effect on acidic and basic strength
Ortho tert butyl benzoic acid will be more acidic than the other one .because former is more bulkier so it will rotate the COOH group out of the benzene ring plane to a more extent .
For NH2 group Ortho to CH3 or C(CH3)3 .Ortho effect never applies NH2 can never go out of the plane .rather this time CH3 and C(CH3)3 goes out of plane .so hyperconjugation effect is lost only inductive effect is present .still tert one will be comparatively less basic because of STERIC INHIBITION OF PROTONATION (SIP) . Due to hindrance nitrogen can't donate it's electron pair easily to a proton