Question

A solution of ammonia has a pH of 11.8. What is the concentration of OH– ions in the solution? Useful formulas..

Answer 1

They are asking you for OH- ions concentration, which is why you have to find the pOH of the solution. You can easily do this with this formula:

pH + pOH = 14

Solve for pOH and you get:

pOH = 14 - pH

Replace the pH with it's value:

pOH = 14 - 11.8
pOH = 2.2

Now that you have the pOH you can find the concentration of OH- ions with this formula:

pOH = -log[OH-]

Solve the formula for [OH-] and you get:

[OH-] = 10^(-pOH)

Now replace pOH with it's value:

[OH-] = 10^(-2.2)
[OH-] = 0.006309 M

The concentration of OH- atoms is 0.006309M or in the scientific notation 6.309×10^(-3)M

Answer 2

Answer:

Its B

Explanation:

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