Arrange these acids in terms of increasing acidity:

CH3COOH, NH3+CH2COOH, CH3CONHCH2COOH

Dr.Bob asked me what NH3+CH2COOH is.NH3+CH2COOH is obtained when 1 mol of glycine is added with a very strong acid,which results in both the amino & carboxyl groups to be fully protonated.
pKa of NH3+CH2COOH is 2.35

OK. Thanks. Here is what I didn't like about your "formula". This is an amino acid (as you noted) BUT I don't think you should write it as NH3 + CH2COOH because there is no such compound as CH2COOH. I just assumed you had made a typo that first time around. I think glycine should be written as H2NCH2COOH and the protonated amino group then would be shown as +H3NCH2COOH. That makes a lot more sense to me. So we are comparing this acid with a pKa of 2.35 with acetic acid with pKa of 4.74 and this is of course stronger. I don't remember the other compound that was to be ranked. If you have the pKa for that one, too, you know where it goes.

Thank you Dr.Bob & sorry for the inconvenience caused to you

To arrange acids in terms of increasing acidity, we need to consider their respective acidity constants, usually represented by pKa values. The lower the pKa value, the stronger the acid.

Given the information, we have the following acids:

1. CH3COOH (acetic acid)
2. NH3+CH2COOH (protonated glycine)
3. CH3CONHCH2COOH (glycine in its zwitterionic form)

Now, let's compare their acidic strengths based on their pKa values:

1. CH3COOH:
Since the pKa value is not provided, we can refer to the pKa value of acetic acid, which is approximately 4.76. Therefore, acetic acid has a higher pKa value compared to the other two acids.

2. NH3+CH2COOH:
Given that the pKa value of NH3+CH2COOH is 2.35, it has a lower pKa value compared to acetic acid. This indicates that NH3+CH2COOH is a stronger acid than CH3COOH.

3. CH3CONHCH2COOH:
No pKa value is provided for glycine in its zwitterionic form. However, it is known that the zwitterionic form of glycine is less acidic compared to ammonium glycine (NH3+CH2COOH).

Based on this analysis, we can arrange the acids in increasing order of acidity:

CH3COOH < CH3CONHCH2COOH < NH3+CH2COOH