Acid Base Equilibria of Chemistry

AP Chemistry Acid-Base Equilibria PH PRACTICE .06 5.7 7.0 8.3 10.44 8.8 x 10^-1 2 x 10^-4 1 x 10^-7 5 x 10^-9 3.6 x 10^-11 H+ H+ H+ H+ H+ OH- OH- OH- OH- OH- 13.94 10.3 7.0 3.56 Write the pH of each solution above the [H+]'s. pH = -log[H+] Label the "Z" diagram as "Acidic," "Basic," and "Neutral." Knowing that the [H+] x 1 [OH-] is always equal to 1 x 10^-14 (fill in the [OH-] for each of the five solutions in the "Z" Diagram. (1 x 10^-14 is called the Dissociation Constant for water, Kw = 1 x 10^-14) 2   Write the "pOH" of each solution below the [OH-]'s. pH + pOH always equals 14 A solution of acid has [H+] = 3.0 x 10^-3 M a. Calculate the [OH-] 3.3 x 10^-12 M b. Calculate the pH 2.52 c. Calculate the pOH 11.48 A solution of base has an [OH-] = 4.25 x 10^-5 M a. Calculate the [H+] 2.35 x 10^-10 M b. Calculate the pH 9.628 c. Calculate the pOH 4.372 Calculate the pH's of the following solutions: 2.53 x 10^-3 M HCl pH = 2.597 2.53 x 10^-6 M HCl pH = 5.597 2.53 x 10^-9 M HCl pH = 8.597 A pH with 3 significant figures is written with 3 numbers after the decimal place. Ch 15 Acids & Bases Which oxide forms a basic solution when mixed with water? (A) K₂O (B) Al₂O₃ (C) CO₂ (D) SO₃ Which 0.1 M solution has the highest pH? (A) sodium carbonate (most basic) (B) sodium chloride (neutral) (C) ammonium carbonate (D) ammonium chloride (acidic) Which is the strongest acid? (Largest Ka) (A) acetic acid (Ka = 1.8 x 10^-5) (B) benzoic acid (Ka = 6.3 x 10^-5) (C) formic acid (Ka = 1.8 x 10^-4) (D) nitrous acid (Ka = 6.0 x 10^-4) What is the order of concentration of the ions and molecules in a nitrous acid solution? (A) HNO₂ > H₃O⁺ > NO₂⁻ > OH⁻ (B) H₃O⁺ > NO₂⁻ = HNO₂ > OH⁻ (C) HNO₂ > NO₂⁻ > H₂O > OH⁻ (D) HNO₂ > H₂O > NO₂⁻ > OH⁻ A water solution of sodium carbonate, Na₂CO₃, has a pH greater than 7 because (A) it contains more carbonate ions than water molecules. (B) it contains more sodium ions than carbonate ions. (C) sodium ions react with water. (D) carbonate ions react with water.   Which species dissociates most completely in water solution? (Strong acid) (A) NH₄⁺ (B) H₂CO₃ (C) HNO₂ (D) HSO₄⁻ According to Brønsted-Lowry Theory, which of these species cannot be amphoteric? (cannot accept or donate a proton) (A) NH₃(aq) (B) NH₄⁺(aq) (C) NH₂⁻(aq) (D) H₂O(l) Which acid reacts with NaOH to form sodium hypochlorite (the ingredient in household bleach)? NaOH + HClO → NaOCl + H₂O (A) HCl (B) HClO (C) HClO₂ (D) HClO₃ Which of these acids is the strongest in aqueous solution? (Strongest Ka) (A) HNO₂ (B) H₂SO₃ (C) HClO (D) HClO₃ Normal rain water has a pH of 5.6. This is best explained by the presence of (A) nitrogen oxides. (B) carbon dioxide. CO₂ in the air (C) sulfur oxides. (D) particulates. In a 0.050 M solution of a weak monoprotic acid, [H⁺] = 1.8 x 10⁻³. What is its Kₐ? (A) 3.6 x 10⁻² (B) 9.0 x 10⁻³ (C) 6.7 x 10⁻⁵ (D) 1.6 x 10⁻⁷ According to the Brønsted-Lowry definition, a base is a substance that (A) increases the hydroxide ion concentration in water. (B) can react with water to form OH⁻ ions. (C) can donate an electron pair to form a covalent bond. (D) can accept a proton from an acid.   What is the pH of a 0.02 M solution of KOH? (A) 12.3 (B) 12.0 (C) 2.0 (D) 1.7 Which couple is not a conjugate acid-base pair? (A) H₂CO₃ and CO₃²⁻ (B) H₂O and OH⁻ (C) NH₄⁺ and NH₃ (D) H₂PO₄⁻ and PO₄³⁻ These acids are listed in order of decreasing acid strength in water. HI > HNO₂ > CH₃COOH > HCN According to the Brønsted-Lowry theory, which anion is the weakest base? (A) I⁻ (B) NO₂⁻ (C) CH₃COO⁻ (D) CN⁻ What is the [H+] in a 0.40 M solution of HOCI? Hoce <-> H+ + OCL- Substance Equilibrium Constant, Ka HOCI 3.5 x 10⁻⁸ Which of these salts will give a basic solution when added to water? (A) NH₄NO₃ (B) NH₄C₂H₃O₂ (C) Ca(NO₃)₂ (D) Ca(C₂H₃O₂)₂ When sodium oxide, Na₂O, is added to water, the major products expected are (A) Na and OH⁻ ions (B) Na⁺ ions and H₂O (C) Na⁺ and O²⁻ ions (D) Na⁺ and OH⁻ ions, and O₂ gas At 0°C, the ion product constant of water, Kw, is 1.2 x 10⁻¹⁵. The pH of pure water at this temperature is (A) 6.88 (B) 7.00 (C) 7.46 (D) 7.56 What is the [H+] in a 0.010 M solution of HCN? The equilibrium constant, Ka, for HCN equals 6.2 x 10⁻¹⁰ (A) 3.6 x 10⁻³ M (B) 1.0 x 10⁻⁷ M (C) 2.5 x 10⁻⁶ M (D) 6.2 x 10⁻¹⁰ M HCN(aq) + HCO₃⁻(aq) ⇌ CN⁻(aq) + H₂CO₃(aq) If the value of the equilibrium constant, K, is less than 1, what is the strongest base in this system? (A) HCN (B) HCO₃⁻ (C) CN⁻ (D) H₂CO₃ The conjugate acid of the bicarbonate ion, HCO₃⁻, in H₂O is (A) CO₃²⁻ (B) H₂O (C) H₂CO₃ (D) OH⁻ The sodium salt, NaA, of a weak acid is dissolved in water and no other substance is added. Which of the following is corrected? (A) [H⁺] = [A⁻] (B) [H⁺] = [OH⁻] (C) [A⁻] = [OH⁻] (D) [HA] = [OH⁻] Which of these ions is predicted to produce the most acidic solution when dissolved in water? (A) Ba²⁺ (B) K⁺ (C) Fe³⁺ (D) Co²⁺ When 0.10 M solutions of the solutes; HClO₄, NH₄Br, KOH, KCN, are arranged in order in increasing [H+], the correct order is (A) KOH < KCN < NH₄Br < HClO₄ (B) KCN < KOH < HClO₄ < NH₄Br (C) HClO₄ < NH₄Br < KCN < KOH (D) NH₄Br < HClO₄ < KOH < KCN