Question

What is the pH of a solution that has [H+] of 1.659e^-9 M

Answer 1

PH of a solution is negative log of its hydrogen ion concentration. Mathematically it can be written as:
$pH = - log[ H^{+}]$
For the said problem pH will be:
$pH = -log [ 1.659 * 10^{-9} ] \\ pH=-(log[1.659]+log[10^{-9}]) \\ pH=-log[1.659]+9log[10] \\ pH=-0.22+9=8.78$

Thus the pH of solution will be 8.78.

Answer 2

Answer is: pH = 8,75.
c(H⁺ or H₃O⁺) = 1,659·10⁻⁹ M = 1,659·10⁻⁹ mol/L = 0,000000001659 mol/L.

pH = -logc(H₃O⁺).

pH = -log(1,659·10⁻⁹ mol/L).

pH = 8,75.
When pH is less than seven (pH<7), solution is acidic.
When is equal seven (pH = 7), solution is neutral.
When pH is greater than seven (pH > 7), solution is basic (like this example).