April 16, 2015 Acids and Bases Strong vs. Weak HCl HNO2 April 16, 2015 Strong acids and bases completely ionize I 1 mol -1mol +1mol +1mol S -1mol +1mol +1mol E 0 April 16, 2015 Weak acids and bases do not completely ionize 1mol -0.0001mol 0.0001mol 0.0001mol +1 -1 NH3 + H2O NH4 + OH 1mol -0.004 mol +0.004 mol +0.004 mol - April 16, 2015 Strong vs. Weak 100% dissociates dissociates minimally April 16, 2015 6 Strong Acids Strong Bases • HCl(aq) → Hydrochloric acid • HBr(aq) → Hydrobromic acid X-OH where X is any metal from • HI(aq) → Hydroiodic acid the 1st or 2nd family (except Be) • HNO3(aq) → Nitric acid • H2SO4(aq) → sulfuric acid • HClO4(aq) → Perchloric acid Weak acids Weak Bases All other acids are weak All other hydroxides are examples: nearly insoluble HF HC2H3O2 NH3 H3PO4 April 16, 2015 Strong vs. Weak, Concetrated. vs. Dilute Strong Acid: Weak Acid +1 -1 H3O +1 X H3O +1 H3O +1 H3O HX HX +1 -1 H3O -1 +1 Conc. X X Conc. HX H3O +1 X-1 +1 HX H3O H3O 10 particles X-1 -1 10 particles -1 +1 X X-1X H3O HX HX X-1 X-1 -1 +1 +1 +1 X H3O +1 H3O H3O X-1H3O HX HX +1 HX H3O + X-1 +1 HX H3O + X-1 Strong Acid: Weak Acid Dilute Dilute +1 2 particles H3O 2 particles +1 H3O X-1 X-1 HX X-1 +1 H3O +1 -1 +1 HX H3O + X HX H3O + X-1 April 16, 2015 p. 47 pH of Strong Acids 1. 0.5M HBr a. Write the hydrolysis reac6on and create an ISE table. + -1 HBr + H2O H3O + Br I 0.5 S -0.5 +0.5 +0.5 E 0 0.5 0.5 +1 b. What is the concentra6on of H3O ions at the end? + 0.5M H3O c. What is the pH of the solu6on? pH = -log[0.5] = 0.301 2. 0.1M HCl a. Write the hydrolysis reac6on and create an ISE table. + -1 HCl + H2O H3O + Cl I 0.1 S -0.1 +0.1 +0.1 E 0 0.1 0.1 +1 b. What is the concentra6on of H3O ions at the end? 0.1M c. What is the pH of the solu6on? pH=1 3. 0.001M HX (stronG acid) a. Write the hydrolysis reac6on and create an ISE table. +1 b. What is the concentra6on of H3O ions at the end? c. What is the pH of the solu6on? April 16, 2015 Determine the pH of a 0.5 M HF solution. Weak + -1 HF + H2O H3O + F I 0.5 S -x -x -x E 0.5-X x x 0.018 0.018 products Ionization Constant, K = reactants + - [H3O ] [F ] x x Ka= = = 6.6 E-4 [HF] 0.5 - X negligible, disregard this"x" (0.5) (6.6 E-4) = x2 2 x =0.00033 plug in X=0.018 M + [H3O ]= 0.018M pH = - log(0.018) = 1.74 April 16, 2015 concentrated weak dilute weak 10 particles partial ionization 3 particles partial ionization HX X-1 HX HX HX H+ H+ HX HX X-1 H+ HX HX HX HX X-1 + -1 + -1 HX + H2O H3O +X HX + H2O H3O +X I 10 I 3 S -2 +2 +2 S -1 +1 +1 E 8 2 2 E 2 1 1 April 16, 2015 concentrated strong dilute weak 10 particles 100% ionization 3 particles 100% ionization + X-1 H+ X-1 H + H + X-1H+ H + X-1 + X-1 H X-1 H -1 + X H + -1 -1H X X -1 -1 X + X + H -1 + H X H X-1 H+ + -1 + -1 HX + H2O H3O +X HX + H2O H3O +X I 10 I 3 S -10 +10 +10 S -3 +3 +3 E 0 10 10 E 0 3 3 April 16, 2015 Review: pOH = 3.71 pH= +1 [H3O ]= [OH-1] = Write the hydrolysis reaction of HBr Write the hydrolysis reaction of NH3. April 16, 2015 Review: pOH = 3.71 pH= 10.29 +1 [H3O ]= 5.13 x 10-11 [OH-1] = 1.95 x 10-4 Write the hydrolysis reaction of HBr + -1 HBr + H2O H3O + Br Write the hydrolysis reaction of NH3. +1 -1 NH3 + H2O NH4 + OH April 16, 2015 Another Review: Write the hydrolysis reaction of 0.1 M HCl and include an ISE table. What is: +1 [H3O ]= [OH-1]= pOH = pH= Is this an acidic or alkaline solution? April 16, 2015 Another Review: Write the hydrolysis reaction of 0.1 M HCl and include an ISE table. + -1 HCl + H2O H3O + Cl I 0.1 S -0.1 +0.1 +0.1 E 0 0.1 0.1 What is: +1 [H3O ]= 0.1M [OH-1]=1x 10-13 pOH = 13 pH= 1 Is this an acidic or alkaline solution? acidic April 16, 2015 Another Review: Write the hydrolysis reaction of 0.015 M HCl and include an ISE table. What is: +1 [H3O ]= [OH-1]= pOH = pH= Is this an acidic or alkaline solution? April 16, 2015 Another Review: Write the hydrolysis reaction of 0.015 M HCl and include an ISE table. + -1 HBr + H2O H3O + Br I 0.015 S -0.015 +0.015 +0.015 E 0 0.015 0.015 What is: +1 [H3O ]= 0.015 [OH-1]= 6.67 E-13 pOH = 12.17 pH= 1.82 Is this an acidic or alkaline solution? acidic.