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PH of weak acids and bases

Chemistry • Acid–Base Equilibria • Knowledge-Based • 5 questions

PH of weak acids and bases Knowledge-Based Download PDF

Chemistry · Acids & Bases · Chemistry · Acid–Base Equilibria

5 Chemistry practice questions on PH of weak acids and bases. Questions that assess core concepts and understanding.

Questions

  1. 1.

    What initial molar concentration of nitrous acid, HNO2\text{HNO}_2 (Ka=4.0×10−4K_a = 4.0 \times 10^{-4}), is required to prepare an aqueous solution with a pH of 2.00 at 25 °C?

    • A) 0.040 M
    • B) 0.16 M
    • C) 0.25 M
    • D) 0.26 M
  2. 2.

    An aqueous solution of a weak monoprotic acid, HA, has an initial concentration of 0.20 M and a measured pH of 3.00 at 25 °C. What is the acid dissociation constant, KaK_a, of this acid?

    • A) 2.0×10−62.0 \times 10^{-6}
    • B) 5.0×10−65.0 \times 10^{-6}
    • C) 1.0×10−51.0 \times 10^{-5}
    • D) 2.5×10−72.5 \times 10^{-7}
  3. 3.

    A 0.020 M aqueous solution of a weak base, B, is 5.0% ionized at 25 °C. What is the pH of this solution?

    • A) 1.70
    • B) 3.00
    • C) 11.00
    • D) 12.30
  4. 4.

    What is the pH of a 0.40 M aqueous solution of a weak base, B, with a base dissociation constant of Kb=2.5×10−6K_b = 2.5 \times 10^{-6} at 25 °C?

    • A) 3.00
    • B) 8.60
    • C) 11.00
    • D) 13.60
  5. 5.

    What is the pH of a 0.10 M aqueous solution of a weak monoprotic acid, HA, with an acid dissociation constant of Ka=1.0×10−5K_a = 1.0 \times 10^{-5} at 25 °C?

    • A) 1.00
    • B) 3.00
    • C) 5.00
    • D) 6.00