Lesson 3.1.12.2

3.1.12.2 Definition and determination of pH Quiz: AQA Chemistry, Unit 1

20 questions

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Lesson 3.1.12.2, Definition and determination of pH: 20 multiple choice questions for the AQA Chemistry (7405), Unit 1: Physical chemistry, written with Revision Ninja.

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The 20 questions

  1. What is the definition of pH?

    • pH = -log10[H^+]
    • pH = -[H^+]/10
    • pH = 1/[H^+]
    • pH = log10[H^+]

  2. A solution has [H^+] = 1.0 x 10^-3 mol dm^-3. What is its pH?

    • 3
    • 11
    • 1
    • -3

  3. A solution has pH 2.5. What is [H^+] in mol dm^-3?

    • 1.0 x 10^-2
    • 3.2 x 10^-3
    • 2.5 x 10^-3
    • 2.5 x 10^-2

  4. What is the pH of 0.050 mol dm^-3 hydrochloric acid, a strong acid?

    • 12.70
    • 1.30
    • 2.30
    • 0.05

  5. What is the pH of 0.0025 mol dm^-3 hydrochloric acid?

    • 2.60
    • 2.25
    • 3.00
    • 0.0025

  6. A solution has pH 4.0. What is [H^+] in mol dm^-3?

    • 1.0 x 10^4
    • 1.0 x 10^-4
    • 4.0 x 10^-4
    • 1.0 x 10^-10

  7. A solution has pH 5.2. What is [H^+] in mol dm^-3?

    • 5.2 x 10^-6
    • 7.9 x 10^-6
    • 6.3 x 10^-6
    • 1.6 x 10^-5

  8. If [H^+] doubles in a solution, by how much does its pH change?

    • It is unchanged
    • It rises by about 0.30
    • It falls by exactly 1.00
    • It falls by about 0.30

  9. What is the pH of 0.010 mol dm^-3 nitric acid, a strong acid?

    • 0.010
    • 12.00
    • 1.00
    • 2.00

  10. What is the pH of 0.0010 mol dm^-3 nitric acid?

    • 3.00
    • 0.0010
    • 2.00
    • 4.00

  11. What is the pH of 0.20 mol dm^-3 hydrochloric acid?

    • 13.30
    • 1.30
    • 0.20
    • 0.70

  12. How many times greater is [H^+] in a solution of pH 2 than in a solution of pH 4?

    • 100 times
    • 10 times
    • 1000 times
    • 2 times

  13. Which solution has the lowest pH?

    • 0.0050 mol dm^-3 hydrochloric acid
    • 0.050 mol dm^-3 hydrochloric acid
    • 0.50 mol dm^-3 hydrochloric acid
    • Pure water at 298 K

  14. A solution of hydrochloric acid with pH 1.0 is diluted 100 times. What is the approximate new pH?

    • 3.0
    • 0.01
    • 7.0
    • 1.0

  15. What is the pH of 0.25 mol dm^-3 nitric acid, a strong acid?

    • 0.60
    • 1.60
    • 0.40
    • 0.25

  16. What is [H^+] in mol dm^-3 for a solution of pH 5.5?

    • 1.8 x 10^-6
    • 3.2 x 10^-6
    • 3.2 x 10^-5
    • 5.5 x 10^-6

  17. Why can the pH of a strong acid solution be used to find its concentration directly?

    • A strong acid does not dissociate, so pH measures the acid molecules directly
    • A strong acid produces the same pH whatever its concentration
    • A strong acid dissociates completely, so [H^+] equals the acid concentration
    • A strong acid dissociates only partly, so [H^+] is always half the acid concentration

  18. Why is a logarithmic scale used for pH?

    • Hydrogen ion concentrations are always exactly ten times the pH value, so the scale is simply a multiplication of the numbers
    • The logarithmic scale makes all acids have the same pH value, so that they are easy to compare in every laboratory test
    • A logarithmic scale is needed because pH cannot be measured with any electrode, so a log scale is used in calculation
    • Hydrogen ion concentrations cover a very wide range, which the logarithmic scale compresses into manageable numbers

  19. A solution has [H^+] = 2.5 x 10^-4 mol dm^-3. What is its pH to one decimal place?

    • 2.5
    • 3.0
    • 3.6
    • 4.0

  20. When the pH of a solution falls by exactly one unit, what happens to the hydrogen ion concentration?

    • It is unchanged, because pH measures only the acid strength
    • It increases by one mol dm^-3
    • It decreases tenfold
    • It increases tenfold

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