Answer:
4.22
Explanation:
According to the question, the pOH of the solution is 9.78. You may recall that pOH is the hydroxide concentration of a solution.
Also pOH = -log[OH^-]. Hence the pOH is obtained from the hydroxide ion concentration.
Finally, pH + pOH =14
Hence;
pH = 14-pOH
pH= 14-9.78 = 4.22
pH= 4.22
