Which acidity of formic acid and acetic acid is strong, and what are the judging methods?

Someone will ask which acid is stronger than formic acid and acetic acid. The following formic acid analyst will explain it to you. 

Generally, the ionization equilibrium constant (K value) of weak acid at 25 C can be used to compare the relative strength of weak acid. The larger the K value, the easier the weak acid is to ionize and the stronger the acidity is. The ionization equilibrium constant of formic acid at 25 C is about the ionization equilibrium constant of acetic acid.

The acidity of formic acid is 10 times higher than that of acetic acid, and the acidity of organic acid with fewer elements is higher, so the acidity of formic acid is higher than that of acetic acid.

The ionization equilibrium constant K value of strong and weak formic acid at 25 C can be used to compare the relative strength of weak acid. The higher the K value, the stronger the acidity. The ionization equilibrium constant of formic acid is about 10 times that of acetic acid at 25 C. The acidity of formic acid is stronger than that of acetic acid. The acidity of organic acid with fewer elements is larger, so the acidity of formic acid is greater than that of acetic acid.

Formic acid is acidic. Put zinc powder into the cup. Formic acid at the same concentration bubbles quickly and the temperature of the cup is high.

Formic acid has strong acidity, and acetic acid has a methyl group which is the electron donor group (SP3 hybrid), so the polarity of OH bond is not as good as formic acid, and the proton of formic acid is easier to leave.