pH & pOH (College Board AP® Chemistry)

Exam Questions

18 mins9 questions
11 mark

The pH of a sample of acid rain at 25 C is 4.55.

What is the [OH-] in the sample?

  • 9.45 M

  • 3.55 x 10-10 M

  • 2.82 x 10-5 M

  • 1.0 x 10-14 M

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21 mark

What is the pH of a solution of NaOH of concentration 0.001 M?

  • 1

  • 3

  • 11

  • 13

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31 mark

Which of the following statements is correct?

  • As temperature increases, the pH value of pure water decreases

  • As temperature decreases, the pH value of pure water decreases

  • The pH of water is unaffected by temperature 

  • Pure water is not neutral 

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41 mark

Two flasks contain two different acids labelled as HA and HB. A student measures the pH of each flask, and finds that they are pH 1 and pH 3 respectively.

Which of the following statements is true?

  • HA is a stronger acid than HB

  • HB is a stronger acid than HA

  • The [H3O+] in the solution of HB is 3 times greater than the [H3O+] in the solution of HA.

  • The [H3O+] in the solution of HA is 100 times greater than the [H3O+]  in the solution of HB.

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51 mark

What is the correct comparison of hydrogen ions between a solution of pH 2 and a solution of pH 4?

  • Twice as large

  • Half as much

  • 1 over 10

  • 1 over 100

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11 mark

Acid

Concentration (M)

pH

X

0.010

2.1

Y

1.5

3.0

Z

2.5

3.5

Which of the following correctly ranks the three monoprotic acids listed in the table above from the strongest to the weakest?

  • X > Y > Z

  • X > Z > Y

  • Y > X > Z

  • Z > Y > X

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21 mark

The Kb value for a base is 8.0 x 10-4 at 298 K.

What is the pKa value for the conjugate acid at this temperature? 

  • 10

  • 1.3 x 10-11

  • 3.1

  • 10.9

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31 mark

When 300 mL of 1.5 M KOH (aq) is added to 400 mL of 0.8 M HBr (aq), the pH of the resulting mixture is closest to

  • 1.8

  • 4.5

  • 7.0

  • 13.3

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