Question

Complete the calculations below for titration of a saturated solution of aluminum hydroxide in water with HCl based on the following data. 3. Al(OH)3(aq) + 3HCI(aq-AICI3(aq) + 3H20(1) Volume of Al(OH)3 solution used: Concentration of diluted HCl solution: Initial Volume of HCl in buret: Final Volume of HCl in buret: 5.00 mL 0.0500 M 2.35 mL 32.86 mL a) Total amount (mol) of HCI added to the saturated Al(OH), solution

number 3, a-e

Answer 1

Total volume of Hcl added = (32.86 - 2.35)ml = 30.51 mL Total amount (mol) of Hcl = 0.050 mol/L times 30.51 mL = 1.525 times 10^- 3 mol 3 mol of Hcl react with 1 mol of Al(OH)_3 1.525 times 10^- 3 mol of Hcl react with 1.525/3 times 10^- 3 = 0.5085 times 10^- 3 mol of Al(OH)_3 concentration of Al(OH)_3 = 0.5085 times 10^- 3 times 1000/5.00 mL = 0.1017 M Al (OH)_3 rightarrow Al^3 + + 30 H^- 3 times 0.1017M 0.3051 M = [OH^-] K_sp = [Al^3 +] [OH^-]^3 = (0.1017) (0.3051)^3 = 2.89 times 10^- 3 M