Several common masking agents used in EDTA titrations are listed paired with a mixture of two metal ions. Classify cach masking agent-metal ion combination by whether the masking agent is capable of masking one of the metal ions and still allowing the other metal ion to react with EDTA or not. Masks one metal ion but not the other Does not mask or masks both metal ions cyanide: Za" and Pa* triethanolamine: A" and P Answer Bank 23-dimercapto-l-propanol: Za* and Ce cyanide: Zn* and Ca* ffuoride: Fe and Zn fluoride: Ar and Fe+

Select Weak Acid as the analyte in the titration interactive. Analyte, 25.0 ml. Weak Acid, 1.0.. Determine the pK, of this weak acid. colortess Indicator No Indicator 14 13.83 pK, = Incorrect pH=2.50 25 50 Titrant Added (mL) Titration Curve Concentration Chart Titrant: Strong Base, 1.0 M MOH 50 0.0 ml + Hd

8. The pH at one-half of the equivalence point in a weak acid – strong base titration was determined to be 4.13. What is the K, for this acid?

You are given a solution of 0.20M CoCl3, 0.15M SnCl2, 0.35M CuCl2, and 0.25M AgCl.Giventhe following table, calculatethe hydroxide concentration needed to precipitate each metal individually so they can be recovered. You do not want more than one metal to precipitate at one time or when you filter the precipitate you will get a mixture.(Optional; calculate the volume of a 0.25M NaOH solution needed to cause this precipitation) b.) Hydroxide needed to precipitate Sn(OH)2 c.) Hydroxide needed to precipitate Cu(OH)2 d.) Hydroxide needed to precipitate AgOH

16.14

For each scenario below, select the color of the solution using the indicator thymol blue during the titration. When you first add indicator to your Na2CO3 solution, the solution is basic (pH ~10), and the color is [Select] At the equivalence point for the titration, the moles of added HCI are equal to the moles of Na2CO3. One drop (or less!) past this is called the endpoint. The added HCI begins to titrate the thymol blue indicator itself. At the endpoint, the indicator color is [Select] When you weren't paying attention and added too much HCI (~12 mL extra), the color is [Select] When you really weren't paying attention and reached the second equivalence point of Na2CO3, the color is ✓ [Select] blue yellow red orange green Question 9

2. Three buffers are made by combining a 1 M solution of acetic acid with a 1 M solution of sodium acetate in the ratios shown below. Buffer 1: Buffer 2: Buffer 3: 1 M acetic acid 10 mL 50 mL 90 mL (i) (ii) (iii) 1 M sodium acetate 90 mL 50 mL 10 mL a. Which of these statements is true of the resulting buffers? pH of buffer 1 pH of buffer 2 > pH of buffer 3 b. Which solution resists changes in pH most effectively?