Exam Review Equilibrium

1. Which of the following is totally dissociated when mixed with water? a. HC2H3HO2 d. HNO2 b. HF e. HBr c. H2SO3

2. A solution of nitrous acid has a pH of 2. 45 2. A solution of nitrous acid has a pH of 2.45. The [H 1+] in mol/L and pOH must be respectively a. 3.5 x 10-3, 11.55 d. 2.8 x 10-12, 12 b. 3.6 x 10-3, 11.55 e. 3.8 x 10-3, 12.55 c. 2.8 x 10-12, 11.6

3i)A solution of barium hydroxide has a [OH1-] = 5.6 x 10-3 mol/L. The pH is which of the following? a. 11.75 d.12.3 b. 12.25 e. none of the above 11.8 ii) If a solution of lithium phosphite has a [H 1+] = 1.6 x 10-8, the pOH must be which of the following? a. 7.80 d. 7.0 b. 6.8 e. 6.20 c. 7.9

4. If the Ka of a weak acid is 1 4. If the Ka of a weak acid is 1.6 x 10-8, the Kb of its conjugate base partner must be which of the following? a. 6.20 d. 6.2 x 10-7 b. 1.0 x10-14 e. 7.80 c. 6.8 x 10-7

5.i) For sulfurous acid the Ka1 = [SO32-][H1+]2 / [H2SO3] d. [HSO31-][H1+] / [H2SO3] [HSO42-][H1+] / [H2SO3] e.[H2SO3] / [SO31-][H1+] 2 c. [SO31-][H1+] 2 / [H2SO3] ii)For cyanide ion (CN1-) the Kb = [OH1-][HCN] / [CN1-] d. [C4-][N 3+ ] / [CN1-] b. [CN1-] / [OH1-][HCN] e. none of the above c. [OH1-][HCN1-] / [CN]

6. When 45 mL of 0. 65 mol/L acetic acid is added to 65 mL of 0 6. When 45 mL of 0.65 mol/L acetic acid is added to 65 mL of 0.45 mol/L sodium hydroxide the resulting mixture is/has a(n) a. neutral d. pH < 7 b. basic e. both c and d c. acidic

7. The pH of a solution of HClO4 was found to be 3. 4 7. The pH of a solution of HClO4 was found to be 3.4. The concentration of this solution in mol/L is which of the following? a. 4 x 10-4 d. 2.5 x 10-11 b. 3.4 e. none of the above c. 0.29

8. A precipitate of zinc hydroxide sits at the bottom of a test tube of distilled water. If the Ksp of this substance is 3.0 x10-16 the [OH1-] in this solution in mol/L is which of the following? a. 8.4 x 10-6 d. 2.4 x10-8 b. 4.2 x 10-6 e. 7.5 x 10-17 c. 1.2 x10-8

a. I b.III and IV c.I and II d.II e.IV 9. Which equilibrium shows a decrease in [products] when the volume increases? I. 2H2(g) + O2(g) <====> 2H2O(g) II. Cl2(g) + PCl3(g) <====> PCl5 (g) III. H2(g) + I2(g) <====> 2HI(g) IV. 2NH3(g) <====> N2 + 3H2(g) a. I b.III and IV c.I and II d.II e.IV

10. Consider the following system at equilibrium: C2H2(g) + Br2(g) + 44 kJ <======> C2H2Br2(g) Which of the following actions would cause the Ke to decrease? I. increasing the volume at constant pressure and temperature II.decreasing the volume at constant pressure and temperature III.increasing the temperature IV.adding bromine gas at constant temperature and pressure V.removing ethyne gas at constant temperature and pressure VI.decreasing the temperature a. I and II b. III c. III and VI d.VI e.IV and V

11. If the equilibrium constant for an equilibrium system is decreased by an increase in temperature then a. [reactants] and [products] decreases b. [reactants] and [products] increases c. [reactants] increases and [products] decreases d. [reactants] decreases and [products] increases e. none of the above

PCl5(g) <=====> PCl3(g) + Cl2(g) 12. The equilibrium shown below was analyzed and the concentrations of PCl5(g), PCl3(g) and Cl2(g) were found, in mol/L, to be 4.5, 2.6 and 1.2. The equilibrium constant must be which of the following? PCl5(g) <=====> PCl3(g) + Cl2(g) a. 1.4 b. 0.84 c. 0.69 d. 1.2 e. 9.8

13. The molar solubility of NiCO3 is 7.6 x10-4 mol/L. The Ksp of nickel(II) carbonate would be which of the following? a. 5.8 x 10-7 d.7.6 x10-4 b. 1.2 x 10-6 e.none of the above c. 4.4 x 10-10

14. In a saturated solution of silver phosphate, the concentration of silver ion is 4.5 x 10-4 mol/L. The Ksp of silver phosphate would be which of the following? a. 6.8 x 10-8 d.1.0 x 10-11 b. 1.4 x 10-14 e. none of the above c. 1.5 x 10-1

15. What is the concentration of a monoprotic weak acid if its pH is 5 15.What is the concentration of a monoprotic weak acid if its pH is 5.50 and its Ka = 5.7 x 10-10? 3.2 x 10-6 b) 2.3 x 10-5 c) 1.8 x 10-2 d) 5.7 x 10-4 e)1.7 x 10-3

16 What is the pH of a 1.24 mol/L solution of HCN(aq) if its Ka = 6.20 x 10-10? 4.56 b) 9.21 c) 4.79 d) 0.093 e) 6.2

17. i) In this reaction HClO4 (aq) + H2SO4 (aq) <======> H3SO4 (aq) + ClO-4 (aq) A conjugate Brønsted-Lowry acid-base pair is a) HClO4 and H2SO4 b) H2SO4 and ClO-4 c) HClO4 and ClO-4 d) H3SO4 and ClO-4 ii) In this reaction HSO4- (aq) + HPO42- (aq) <======> SO42- (aq) + H2PO4 - (aq) a) HSO4- (base) and SO4 2- (acid) b) HPO42- (base) and H2PO4 – (acid) c) HSO4- (acid) and HPO42- (base) d) HPO42- (acid) and H2PO4 - (base)

18. i) What volume of 0.0400 mol.L1- HCl(aq) is required to completely neutralize 200 mL of 0.0200 mol.L1- NaOH(aq)? 50.0 mL b) 100 mL c) 150 mL d) 200 mL i) What volume of 0.0400 mol.L1- H2SO4(aq) is required to completely neutralize 200 mL of 0.0200 mol.L1- NaOH(aq)? a) 50.0 mL b) 100 mL c) 150 mL d) 200 mL

Assume the Ka of acetic acid is 1.8 x 10-5. 19. 28 mL of 0.36 mol/L acetic acid is titrated with a standardized 0.43 mol/L KOH solution. Calculate the pH of the solution after 21 mL of the KOH solution has been added. Assume the Ka of acetic acid is 1.8 x 10-5. a) 7.0 b) 8.5 c) 3.9 d) 3.2 e) 9.4