equation and will the resulting pH be above or below 7? 4. In a titration, which of the following combinations would result in an equivalence point with pH greater than 7.0? *Hint: find the resulting salt from each reaction and see if and how it undergoes hydrolysis A. HCl and NaOH B. HNO3 and NH3 C. HBr and NaCH3COO D. CH3COOH and NaOH 5. Calculate the pH of a 0.20M KCN solution (Type 1 Kb problem after considering hydrolysis). V) Indicators Indicators are used to signal the equivalence point (when _______________ __________________________________) of an acid-base titration using a colour change. An indicator is a solution of a weak organic acid (an acid that contains ___________), HIn, and its conjugate base, In-, at equilibrium. The acid form of the indicator, HIn, is a different colour than the conjugate base form, In-. The following is the general equilibrium for any acid-base indicator: HIn + H2O In- + H3O+ Let’s look at how an indicator equilibrium works in solution using the indicator bromthymol blue: HIn + H2O In- + H3O+ For bromthymol blue: yellow blue If [HIn] > [In-], the system favours the _______side and the solution will be a _____________ colour. If [In-] > [HIn], the system favours the ___________ side and the solution will be a _______________ colour. What happens to the equilibrium if bromthymol blue is put into an acidic solution, and what is the resulting solution colour? HIn + H2O In- + H3O+ yellow blue
equation and will the resulting pH be above or below 7? 4. In a titration, which of the following combinations would result in an equivalence point with pH greater than 7.0? *Hint: find the resulting salt from each reaction and see if and how it undergoes hydrolysis A. HCl and NaOH B. HNO3 and NH3 C. HBr and NaCH3COO D. CH3COOH and NaOH 5. Calculate the pH of a 0.20M KCN solution (Type 1 Kb problem after considering hydrolysis). V) Indicators Indicators are used to signal the equivalence point (when _______________ __________________________________) of an acid-base titration using a colour change. An indicator is a solution of a weak organic acid (an acid that contains ___________), HIn, and its conjugate base, In-, at equilibrium. The acid form of the indicator, HIn, is a different colour than the conjugate base form, In-. The following is the general equilibrium for any acid-base indicator: HIn + H2O In- + H3O+ Let’s look at how an indicator equilibrium works in solution using the indicator bromthymol blue: HIn + H2O In- + H3O+ For bromthymol blue: yellow blue If [HIn] > [In-], the system favours the _______side and the solution will be a _____________ colour. If [In-] > [HIn], the system favours the ___________ side and the solution will be a _______________ colour. What happens to the equilibrium if bromthymol blue is put into an acidic solution, and what is the resulting solution colour? HIn + H2O In- + H3O+ yellow blue
acid-baseiibookletv6.docx