The salt used in the solution with a pH of 8.07 after adding 0.1M of the salt depends on its composition and can result in a basic, acidic, or neutral solution.
The pH of a solution containing a salt is influenced by the nature of the salt formed during the reaction between an acid and a base. In the case of a salt derived from a weak acid and a strong base, the resulting solution tends to be basic. This is because the anion from the weak acid does not readily donate protons, leading to a relatively higher concentration of hydroxide ions, thereby increasing the pH.
Conversely, when the salt is formed from a strong acid and a weak base, the solution tends to be acidic. The cation from the strong acid doesn't readily accept protons, resulting in a higher concentration of hydrogen ions and a decrease in pH.
For salts derived from both a strong acid and a strong base, the resulting solution is neutral. The dissociation of ions from the strong acid and base is equally effective in producing both hydroxide and hydrogen ions, maintaining a balance and resulting in a neutral pH around 7.