6. Chemical Quantities & Aqueous Reactions
Solution Stoichiometry
6. Chemical Quantities & Aqueous Reactions Solution Stoichiometry
10PRACTICE PROBLEM
The amount of gold in ore can be determined by redox titration. Gold is first oxidized from Au to Au3+ by adding 1:3 v/v HNO3:HCl and then it is precipitated using excess hydroquinone (C6H6O2) solution as shown below:
2 Au3+(aq) + 3 C6H6O2(aq) → 2 Au(s) + 6 H+(aq) + 3 C6H4O2(aq)
The excess hydroquinone is titrated with cerium sulfate (back titration). Calculate the mass percent of Au in a 0.4685 g ore sample if after back titration it was found that 35.68 mL of 0.0250 M C6H6O2 was used to precipitate all of the Au3+ in the solution.
The amount of gold in ore can be determined by redox titration. Gold is first oxidized from Au to Au3+ by adding 1:3 v/v HNO3:HCl and then it is precipitated using excess hydroquinone (C6H6O2) solution as shown below:
2 Au3+(aq) + 3 C6H6O2(aq) → 2 Au(s) + 6 H+(aq) + 3 C6H4O2(aq)
The excess hydroquinone is titrated with cerium sulfate (back titration). Calculate the mass percent of Au in a 0.4685 g ore sample if after back titration it was found that 35.68 mL of 0.0250 M C6H6O2 was used to precipitate all of the Au3+ in the solution.