Which weak acid would be best to use when preparing a buffer solution with a ph of 9.80?

Certain solution possesses the ability to resist an appreciable change in hydrogen ion concentration  (i.e, pH) when small amount of acids or bases are added to these solutions. The resistance of solution is called 'Buffer capacity' and the solutions are called 'Buffer solutions'.Buffer solution usually consist of weak acid or base along with its salt. Equivalent mixture of Glycine and its salt with sodium hydroxide  is used for preparing buffer solution with pH equal to 9.80.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.