2>1>3> NH3

actually, the order shud be 3>2>1>NH3 coz more the number of alkyl groups, more is the electron density on N.

 

but in aq soln, the basicity depends upon +I effect, H-bonding, streic effects

 

due to +I effect, 3>2>1 is correct order

due to hbonding, 1>2>3

due to steric effect, 2>3>1

 

so, in short ---->

2>1>3>NH3