1. pH Determination of a Weak Acid What is the pH of a 2.90 M ethylamine (C2H5NH2) solution at 298 K?

What is the pH of a 2.90 M ethylamine (C2H5NH2) solution at 298 K? The basicity constant Kb for C2H5NH2 is Kc = 6.5 x 10E-4. a. 2.72 b. 12.41 c. 11.28 d. 1.59 e. 1.36 f. 11.10 g. 2.90 h. 12.64 The pH of a 2.1 M solution of a weak acid, HA, at 298K is 1.85. What percent of the acid has dissociated? a. 4.06 % b. 11.8 % c. 0.67 % d. 33.7 % e. 8.44 % f. 1.28 % g. 6.73% h. 0.41 % i. 12.8 % j. 3.37 % What is the pH of a 0.75 M NaOH solution at 60°C? The equilibrium constant Kw for water at 60°C (333 K) is 9.60 x 10E-14. a. 14.12 b. 13.88 c. 12.72 d. 0.30 e. 13.32 f. 14.62 g. 13.50 h. 0.12 i. 12.89 j. 14.30 0.40 moles of a diprotic acid, H2A, is dissolved in 250 mL of water. The Ka1 of this acid is 1.0 x 10E-5 and Ka2 is 1.0 x 10E-9. What is the concentration of the di-anion, [A^2-], in this solution (in M)? a. 1.0 x 10E-5 b. 1.0 x 10E-10 c. 4.0 x 10E-3 d. 1.6 x 10E-5 e. 1.0 x 10E-9 f. 3.2 x 10E-3 g. 2.0 x 10E-6 h. 1.3 x 10E-7 i. 3.2 x 10E-5 j. 4.0 x 10E-5 Which of the following acetate anions is the strongest base?a. CH2ICOO- b. CCl3COO- c. CF3COO- d. CH2BrCOO- e. CH2ClCOO- f. CHF2COO- g. CI3COO- h. CHCl2COO- i. CBr3COO- j. CH2FCOO- What is the pH at the equivalence point when 100 ml of 0.15 M hydrofluoric acid HF is titrated with 0.5 M sodium hydroxide NaOH at 298K? (Ka(HF) = 7.2 x 10-4 ) a. 7.0 b. 8.1 c. 5.9 d. 6.1 e. 7.9 f. 10.1 g. 8.9 h. 4.3 i. 7.4 j. 11.1 What is the pH at the stoichiometric point (end point) for the titration of 50 ml of 0.20 M methyl amine CH3NH2 (aq) with 0.20 M perchloric acid HClO4(aq)? For methyl amine (CH3NH2), Kb = 3.6 x 10^–4. a. 5.93 b. 2.37 c. 2.22 d. 5.78 e. 7.00 f. 8.22 g. 11.63 h. 9.56 i. 8.07 j. 11.78 At 298K, 125 ml of 0.60 M potassium hydroxide KOH is added to 175 ml of 0.40 M hydrochloric acid HCl. What is the final pH? a. 13.4 b. 1.4 c. 0.9 d. 12.2 e. 13.1 f. 2.2 g. 7.0 h. 0.6 i. 12.6 j. 1.8