What is the pH of a solution with [H3O+] = 1 x 10-9 M?

My answer is pH=9. is that correct

yes

Yes, that is correct. The pH of a solution can be calculated using the formula:

pH = -log[H3O+]

In this case, [H3O+] is given as 1 x 10-9 M. Plugging this value into the formula:

pH = -log(1 x 10-9)
= -log(1) + log(10-9)
= -0 + (-9) [Using the logarithmic property: log(a*b) = log(a) + log(b)]
= -9

Therefore, the pH of the solution is 9.

Yes, your answer is correct. The pH of a solution can be calculated using the formula:

pH = -log[H3O+]

In this case, the concentration of H3O+ is 1 x 10-9 M. So, substitute the value into the formula:

pH = -log(1 x 10-9)

To evaluate this expression, take the negative logarithm (base 10) of the concentration using a calculator:

pH = -log(1 x 10-9)
= -(-9) (since log(1 x 10-9) = -9)
= 9

Therefore, the pH of the solution with [H3O+] = 1 x 10-9 M is 9.