Question

The pH of a softdrink is determined to be 4.0. What is the [OH-] of the drink?

a
1.0 x 10-10 M
b
1.0 x 10-4 M
c
4 M
d
10 M

Answer 1

The correct hydroxide ion concentration ([OH-]) for a soft drink with a pH of 4.0 is 1.0 x 10^-10 M, found using the ionic product of water and the established relationship between pH and pOH.

Step-by-step explanation:

The pH of a soft drink is given as 4.0, and we are asked to find the hydroxide ion concentration ([OH-]) in the drink. To solve this, we use the ionic product of water (Kw), which at 25°C has a value of 10⁻¹⁴ M². Since pH + pOH = 14, we can find pOH by subtracting the pH from 14. Thus, pOH = 14 - 4 = 10. The concentration of hydroxide ions is then found by taking the inverse log of -pOH, which gives us [OH-] = 10⁻¹⁰ M.

Therefore, the correct answer is a. 1.0 x 10⁻¹⁰ M.

Answer 2

Answer: A) 1.0 x 10-10 M

Explanation: The pH is 4.0, and pOH + pH = 14, so pOH = 10. [OH-] = 10^-pOH, so for this drink, [OH-] = 10^-10 M, or 1.0 x 10^-10 M.