Final answer:
The pH of the solution decreases when sodium formate is added.
Step-by-step explanation:
The pH of a solution is a measure of its acidity or alkalinity. A lower pH indicates a more acidic solution, while a higher pH indicates a more alkaline solution. In this case, the initial solution of 0.03 M formic acid has a pH of 2.63, indicating that it is acidic. When 0.03 M sodium formate is added, the formate ions will react with the H+ ions from the formic acid, shifting the equilibrium towards the formation of more undissociated formic acid molecules. This will decrease the concentration of H+ ions in the solution, resulting in a higher pH. Therefore, the correct statement is:
a. the pH decreases.
Learn more about pH of solution
Final answer:
If 0.03 M sodium formate is added to a 0.03 M formic acid solution with a pH of 2.63, the equilibrium shifts to the left and pH increases.
Step-by-step explanation:
When 0.03 M sodium formate (NaHCOO) is added to a 0.03 M formic acid (HCOOH) solution with a pH of 2.63, the presence of the formate ion will cause a shift in the equilibrium of the acid dissociation reaction towards the left because of Le Chatelier's principle. This addition will result in the formation of more undissociated formic acid and consume hydronium ions (H3O+), increasing the pH of the solution. The correct statement is that the equilibrium position is shifted to the left (b). Therefore, the [H3O+] concentration will decrease, not increase, and the concentration of HCOOH (formic acid) will not decrease but instead will move towards equilibrium with its conjugate base. Thus, the correct answer is (b), the equilibrium position is shifted to the left.