Answer:
D. None of these can be assumed
Explanation:
- A is incorrect because pH is the concentration of ions, meaning a solution made with a weaker acid can be stronger if the concentration is changed by changing its volume. Since we cannot assume that the acid is unchanged in volume, we cannot assume an acid is stronger than the other
- B is incorrect because it states that Ka, the acid disassociation constant, is higher for acid A. Although this could be implied, this can only be known for sure when the solution is participating in a equilibrium reaction, where products and reactants are changing into each other at the same rate. Since the pH value can only be use to calculate the concentration and we would need to know the concentration of all reactants in order to find Ka, this answer is not definitive, and therefore is not always true
- C is incorrect because pH of the acid could depend on the concentration of said acid, but this is also not able to be assumed, as concentrating the acid will not result in such a drastic pH change, especially when we do not know how high its pH started as.
Therefore, since no answer can be said for sure, D is the correct answer.
