How to solve this question?
sodium formate and formic acid are weak acid/ conjugate base. this would make the solution a buffer system. in a buffer system, diluting would not indeed change the pH of the system.
The pH of a buffer solution is primarily determined by the ratio of the concentrations of the weak acid and its conjugate base and their respective pKa values. This ratio helps maintain a relatively constant pH within a certain range.
This is why the molarity will stay 4.15 M.
hope this helps