Which is the stronger base, NH3 or H2N-CH2COOH?
H2N-CH2COOH is stronger because of the electron donating ability of CH2COOH
The information I can find is that the pKa for the amine group is 9.6. pKa for NH3 is 9.25 which would make NH3 the stronger acid; thus the weaker base. Check my thinking.
To determine which base is stronger between NH3 and H2N-CH2COOH, we need to analyze their chemical structures and their behavior as bases.
NH3, also known as ammonia, is a weak base. It can accept a proton (H+) to form its conjugate acid, NH4+ (ammonium).
H2N-CH2COOH, on the other hand, is an amino acid called glycine. It contains both an amino group (NH2) and a carboxylic acid group (COOH).
To compare their basicity, we can evaluate the stability of their conjugate acids.
The conjugate acid of NH3 is NH4+ (ammonium ion):
NH3 + H+ → NH4+
The conjugate acid of H2N-CH2COOH is H3N+CH2COOH (glycine in its protonated form):
H2N-CH2COOH + H+ → H3N+CH2COOH
Now, glycine has an additional carboxylic acid group (COOH) compared to ammonia, which can stabilize the protonated form by resonance. Resonance occurs when electrons are delocalized, resulting in greater stability.
Due to this extra stabilization, the conjugate acid of glycine (H3N+CH2COOH) is more stable compared to the conjugate acid of ammonia (NH4+).
Since a stronger base has a weaker conjugate acid (more stable), H2N-CH2COOH (glycine) is a stronger base compared to NH3 (ammonia).