How would you classify a solution if [OH-] = 4.2 x 10-8 M?
A. Acidic
B. Basic
C. Neutral
D. It is impossible to tell based on the information given
would it be B? please explain
Let's think about this. If a neutral solution is 1E-7 M for (H^+) and 1E-7 M for (OH^-), that means for the solution to be basic the (OH^-) must be larger than 1E-7 M. Is 4.2E-8 M larger than 1E-7 M?
The answer is A
To determine the classification of a solution based on its hydroxide ion concentration ([OH-]), we can use the concept of pH. The pH scale measures the acidity or basicity of a solution. A pH value less than 7 indicates acidity, a pH equal to 7 indicates neutrality, and a pH greater than 7 indicates basicity.
To find the pH, we can calculate it using the expression: pH = -log[H+]. However, in this case, we are given the concentration of hydroxide ions ([OH-]). The hydroxide ion concentration can be used to calculate the pOH, which is the negative logarithm of the hydroxide ion concentration: pOH = -log[OH-].
Given that [OH-] = 4.2 x 10^(-8) M, we can calculate the pOH as follows:
pOH = -log(4.2 x 10^(-8)) = 7.38.
Since the pH + pOH = 14 (at 25°C), we can find the pH by subtracting the pOH from 14:
pH = 14 - pOH = 14 - 7.38 = 6.62.
According to the pH scale, a pH of 6.62 is acidic. Therefore, the correct classification for the solution with [OH-] = 4.2 x 10^(-8) M is A. Acidic.