Three buffers are prepared using equal concentrations offormic acid (HCOOH) and sodium formate, hydrofluoric acid (HF) andsodium fluoride, and acetic acid (CH3COOH)and sodium acetate. Rank the three buffers from highest to lowest pH.

The question given is incomplete because the Ka of the acids were not provided. I got the complete question from google as below:

Three buffers are prepared using equal concentrations offormic acid (HCOOH) and sodium formate, hydrofluoric acid (HF) andsodium fluoride, and acetic acid (CH3COOH)and sodium acetate. Rank the three buffers from highest to lowest pH.

According to the text, the Ka of the acids are as follows:

HCOOH: 1.77 × 10–4

HF: 6.8 × 10–4

CH3COOH: 1.76 × 10–5

Based on the Ka values of the acids given, the arrangement of the acids given from the highest to lowest pH is as below:

HF > HCOOH > CH3COOH

Explanation:

For acids, the higher the pH, the higher the pK , also, the lower the pH, the lower the pK.

then

pKa = -log(Ka)

So,

The acid with the highest pH will have the highest Ka value , while the acid with the lowest pH will have the lowest Ka value.

Thus, based on the Ka values of the acids given, the arrangement of the acids given from the highest to lowest pH is as below:

HF > HCOOH > CH3COOH

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."