Question

What is the ph of a solution made by mixing 0.30 mol naoh, 0.25 mol na₂hpo₄, and 0.20 mol h₃po₄ with water and diluting to 1.0l?

(a) 7.2
(b) 5.3
(c) 8.5
(d) 6.0

Answer 1

The pH of the solution is approximately 5.3.

Step-by-step explanation:

To determine the pH of the solution, we need to consider the dissociation of the acids and bases present. NaOH is a strong base that completely dissociates in water, while H3PO4 and Na2HPO4 are weak acids that partially dissociate. Since we have both weak acids and bases, we need to consider the salt formed during the reaction.

The pH of the solution can be calculated by finding the concentration of H+ ions using the dissociation constants of H3PO4 and Na2HPO4. By calculating the concentration of H+ ions and taking the negative logarithm, we can find the pH of the solution. In this case, the pH of the solution is approximately 5.3, option (b).