Question

A sample of lemon juice has a pH of 3. What is the [OH-] concentration of the lemon juice? A) 11 B) 1 X 10+3 C) 1 X 10-3 D) 1 X 10-11

Answer 1

pH scale is used to determine the acidity of a solution

pH is calculated using the H⁺ concentration

pOH scale is used to determine how basic a solution is

pOH is calculated using the OH⁻ concentration

pH and pOH are related in the following formula

pH + pOH = 14

pH = 3

pOH = 14 - 3

pOH = 11

pOH is calculated using the following formula

pOH = - log[OH⁻]

[OH⁻] = antilog(-pOH)

[OH⁻] = antilog(-11)

[OH⁻] = 1 x 10⁻¹¹ M

the [OH⁻] concentration of lemon juince is D) 1 x 10⁻¹¹ M

Answer 2

PH+pOH=14
pOH=14-pH=14-3=11
pOH=-log[OH⁻]
11=-log[OH⁻]
[OH⁻]= 10⁻¹¹ =1*10⁻¹¹ 
Answer is D.