Final answer:
The pH of the solution with a hydronium ion concentration of 1×10-9 M is calculated using the formula pH = -log [H3O+] and the result is 9.0, making the solution basic.
Step-by-step explanation:
The question asks to determine the pH of a solution when the concentration of hydronium ions [H3O+] is known to be 1×10-9 M. The formula to calculate pH is pH = -log [H3O+]. Using this formula, we substitute the given concentration to find the pH:
pH = -log(1×10-9) = 9.0
Therefore, the correct answer is E. 9.0, indicating that it is a basic solution since the pH is greater than 7.
The pH of a solution can be found by taking the negative logarithm (base 10) of the hydrogen ion concentration [H3O+]. In this case, the [H3O+] is 1x10^-9 M. So, the pH is -log(1x10^-9), which is equal to 9. Therefore, the answer is E. 9.0.