Chromium(lI) acetate, or chromous acetate, is perhaps the most accessible repres

Question

Chromium(lI) acetate, or chromous acetate, is perhaps the most accessible representative of the large class of complexes with an unusual type of metallic bonding A major point of this lab exercise will be to not only prepare the complex, but further study the understanding that it has brought to bonding theory.12 You will work in a relatively oxygen free environment and study the following oxidation-reduction couple This experiment will be conducted in groups of four since the setups use the same N2 tank and must be synchronized. Bubble N2 through 25 mL of water in flask C (size 250 ml, Figure 1) for at least 10 min. Then dissolve 7.5 g of CrCl3-H20 followed by 6 g of mossy zinc. Set up the apparatus securely so that the side-arm tube B is just below the surface of the water in the beaker. Use a disposable pipette on the end of the tube B. Use an adjustable platform under B, C or D if available. 30 mL of conc. HCI should be added to the dropping funnel A. Solution D is prepared by slowly adding 45 g of sodium acetate to 40 mL of water in a 250 mL Erlenmeyer flask. Mark the level of the liquid with a Sharpie marker. This concentrated solution should be warmed until it is clear and bubble free (~5 min). At this point, the flask should be closed with a size 6 stopper that is connected to a balloon containing 125 mL of N2 gas. When cooled, the flask should be fitted to the transfer arm and sealed with parafilm. Keep at ambient temperature and do not agitate the flask to avoid Figure 1. The apparatus for the redox reaction maintains an oxygen-free environment. crystallization Slowly and with care, add concentrated HCI to the reaction solution from dropping funnel (or buret) A until the solution becomes a permanent, clear blue color (~ 25 mL conc. HCI). Note: take care during the addition so that no solution rises into the transfer tube leading to flask D. With the production of the blue solution C, transfer can be effected by manually pinching tube B. During transfer, raise D so that the tube is just under the surface of the solution. Swirl D for good mixing. A drop or two of additional HCI may be necessary for complete transfer (it takes 10 to 20 minutes), or use the N2 line to push the solution out. When complete, quickly separate and re stopper D with the nitrogen balloon Collecting the crystals without oxidation by air is the hardest part of the procedure. Using a large Buchner funnel and double filter paper, rinse the solid with four 25 mL portions of ice-cold, oxygen-free (degassed) DI water. Never let the crystals lose a covering of rinse water. After the water, rinse with three small portions (enough

Explanation / Answer

In this synthesis, zinc metal serves as the strong reducing

agent: Zn

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.