Question

What is the pH of an acid with a [H+] of 1.0 x 10&-4 M? 1. 4 2. 10 3. 1 4. 7

Answer 1

PH scale is from 1 to 14 and indicates how acidic or basic a solution is. To find pH or pOH we need to know the H⁺ ion concentration or OH⁻ concentration.
pH can be calculated using the following equation;
pH = -log[H⁺]
the H⁺ concentration of the given acid is 1.0 x 10⁻⁴ M. substituting this we can find the pH 
pH = -log[1x10⁻⁴]
pH = 4
answer is 1) 4