Procedure solutions you are using are fairly concentrated and require ca Caution

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Procedure solutions you are using are fairly concentrated and require ca Cautions: Many of the acid and base mmediately and flush with plenty of water if they contact your skin. handling. Clean up spills obtain a Bunsen bumer, striker, centrifuge tubes.test tube rack. wo I00 ml beakers, two watch one (to cover the beakers), flame test loop. 50 mL beaker, sized for a water bath to hold a beaker centrifuge tube. stir rods. eyedropper M HCI in the 50 mL beaker, obtain a few mLof6 Light the Bunsen burner and adjust it to a hot flame. unknown solution in the other about 5 mL of the test solution in one labeled 100 mL beaker, test loop labeled 100 ml beaker, and two pi paper. Clean the flame pping first into the acid and then heating it in the hottest pan of the burner name. Repeat this procedure until the loop the does not discolor the When the loop is clean and cool into the solution and then heat it in dip it ion. hottest part of the flame Afluffy, intense yellow flame is confirmation of the presence of the sodium (Note that the flame s over when the loop is glowing. The glowing wire wi cause a yellow flame which is not as intense as the sodium fame his is not confirmation of the sodium ion) Clean the flame test loop before performing the test on your unknown solution Moisten a piece of litmus paper and stick it to the bottom of the watch glass, Add 1-2 mL of 6 M NaOH solution to the test solution and cover the beaker with the watch glass. Hold the watch glass on the beaker and warm the beaker with your hand for a minutes. As confirmat f the ammonium cation, the red litmus paper tums blue as ammonia a few dissolves on gas. released from the solution, into the moisture th he litmus paper. raising its pH. You may also wish to smell the ammonia for confirmation: remove atch glass and waft the vapors from the beaker toward your nose. If your hands are not warm enou gh to this test, heat the beaker very gently over a low.cool bumer name 4 Prepare a boiling water bath in a beaker sized for your centrifuge tubes while starting on the nextsteps obtain 2 mLof fresh test solution in one labeled centrifuge tube and 2 5 of 6 MHC to the solution and mix the contents thoroughly in another centrifuge tube. Add drops by adding 1 or 2 more M centrifuge the mixture and test the precipitation for completeness HCI. Once the tation is complete, decant the supermate into a clean test tube. Wash the precipitate centrifuge, and combine the wash supernate with the first supernate PI) with 5 drops of deionized water, (SI). Add 2mLof deionized water to precipitate P1. break up and stir the precipitate briefly and place the test tube in the boiling water bath. Heat the tube for two minutes. and stir up the precipitate four times in this time. Decant the supernate (S2) into a clean tube Remove the tube from the hot water bath and centrifuge and set the tube with the white precipitate (P2) aside. Add 2 drops off 0.1 M Na,Cro. to the supernate bright yellow precipitate confirms the presence of lead Add 6 M NH, drop wise to precipitate P2 until the precipitate dissolves. Be sure to mix the contents of the tube while adding the ammonia solution. Once the precipitate is completely dissolved (S3) add 6 drops of 6 M HNO,. A white precipitate confirms the presence of silver. drops of concentrated NH, solution to solution si. A deep blue color Go to the hood and add 3 confirms the presence of copper. Centrifuge this tube to separate the precipitate (P4) from the blue pernate. Decant the blue solution into a waste beaker and he precipitate with 1 mL of deionized water. Centrifuge again and decant the supernate into waste Prepare a fresh solution of the complex ion [Sn(OH) P by placing two drops of 1 M SnCl, est tube. Add 6 M NaOH dro only until into a C the precipitate that forms with the first drop is completely redissolved. Add 3-5 drops of this solution to P4 and mix the tube contents thoroughly. Centrifuge the tube. A dark graylblack coloration in the precipitate confirms the presence of bi smuth in the sample. as uired by your instructor. Rinse the tubes and discard the rinsings Dispose of all solutions into w with the same Wash the tubes and all other glassware with soap and water, giving them final water

Explanation / Answer

Precipitate soulble If we use 6M HNO3 in place of 6M HCl.

Metal salt + HCl ---------> Metalchloride (Solid)

Metal salt + HNO3 ---------> Metal Nitrates( soluble in water)

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