Question

Which of the following statements are true?

pH = log[H3O+]
An increase in the pH of a solution means the hydrogen ion concentration increased.
A neutral solution has pH = 7.
A pH change of 1 means a 10-fold change in [H+].
A. I and III only
B. II and III only
C. III and IV only
D. I, II, and III only

Answer 1

For I
Remember the formulas!

pOH = -log_10([-OH])

For II Does an increase concentration mean that hydrogen ion concentration go up? Think about the definition of pH (pH = -log_10([+H])) and look at a scale. Make sure you are right.

For III Yeah this is obvious

For IV

Well by definition:

pH = -log_10([+H])

because log_10(x) = y is the same as 10^(y) = x
We get:

10^-pH = [+H]

Play with this formula.

Remember what exponents are:

x^5 = x*x*x*x*x
10^3 = 10*10*10
etc

Answer 2

So the answer is C?

Answer 3

yeah that should be correct.