Question

What is the pH if the concentration of OH ions is 2.7 x 10^-3 M? (Hint: This is a two-part question).

a) 10.3
b) 2.7
c) 11.3
d) 7.3

Answer 1

To find the pH when the concentration of OH- ions is 2.7 x 10^-3 M, calculate the pOH first and then subtract it from 14 to get the pH. The closest answer is 11.3.

Step-by-step explanation:

The pH of a solution when the concentration of hydroxide ions (OH-) is 2.7 x 10-3 M can be determined by calculating the pOH first and then using the relationship between pH and pOH. The pOH is calculated using the expression pOH = -log[OH-]. After calculating the pOH, we use the following relationship: pH + pOH = 14. To find the pH, subtract the pOH from 14.

Let's calculate the pOH first:

pOH = -log(2.7 x 10-3) = 2.57

Now, we calculate the pH:

pH = 14 - pOH = 14 - 2.57 = 11.43

Therefore, the closest answer to 11.43 from the provided options is c) 11.3.