How to solve for the answer

Question

I would like to get help on how to solve this problem. What is the H3O+ of a solution with a pH of 1.8?

Answer 1

There's an equation we need in order to solve this problem:

(1) pH = -log[H₃O⁺]

We're given the pH and need to solve for [H₃O⁺].

Rearranging equation (1) by multiplying each side by (-1) and raising it to the power of 10 gives:

10^-pH = 10^log[H3O+]

Since 10^logx = x,

10^-pH=[H₃O⁺]

∴10^-1.8 = [H₃O⁺] = 0.0158M

Answer 2

To get the concentration of [H₃O⁺], you take 10 and raise it to the NEGATIVE power of the pH.

So, [H₃O⁺]= 10^-pH=10^-1.8 ≈ 0.016 M