Chem
posted by natalie .
Can a 100ml sample of 3.0m H2 SO4 could be neutralized by 100 ml of 3.0m NH3

I will assume you intended to write 3.0 M and not 3.0 m.
2NH3 + H2SO4 ==> (NH4)2SO4
How many mols H2SO4 do you have? That's M x L = 0.1 x 3.0 M = 0.3 mol.
Look at the equation. That will take 2 x that amount or 0.6 mol NH3. You have only 0.3 x 0.1 = 0.3; therefore, only about 1/2 the H2SO4 will be neutralized.