In this experiment I need to identify eleven clear and colorless solutions using analytical techniques. The assignment
Question:
In this experiment I need to identify eleven clear and colorless solutions using analytical techniques. The assignment gives a list of chemical compounds that are aqueous solutions. By using flame tests and pH tests and by mixing the solutions with one another I will have to match them up. Here are the list of solutions (they will be numbered 1 to 11 in the lab but their identities will not be known): 0.1M HCl 3% H2O2 0.1 M Na2C2O4 0.1M NH4Cl 0.1M Al(NO3)3 0.1M Ba(NO3)2 0.1M AgNO3 0.1M Na2CO3 0.1M Mn(NO3)2 0.1M Na2S2O3 0.1M ZnCl2 I have reviewed these chemicals but I am having trouble distinguishing which test to use and at what point in the lab. Some of the analytical tests that the pre-lab reading mentioned was the pH test. This can be used to identify any solutions that are acidic or basic. The pH of a neutral solution is 7 while acids have lower pH and bases have higher pH. We are told due to the imprecision of pH paper measurements you should only use this as a first test for strong acids and bases. [Among the solutions you will be using the strong acids all contain H+ and the strong bases contain CO3^-2]. We are told another analytical test is the flame test - "Many metal cations when exposed to the heat of a flame will emit brightly colored light. Of the cations you will be analyzing Ba^2+ produces a yellow flame and Na+ produces an orange flame. It may be difficult to distinguish the orange sodium flame from the ordinary flame color so do not use the flame test as the first test to find the Na+ solutions." The remaining tests involve mixing together two or more of the unknown solutions and observing any reaction. One common result will be the formation of a solid precipitate. An insoluble precipitate will form from certain pairs of cations and anions.
Chemistry The Central Science
ISBN: 978-0321696724
12th edition
Authors: Theodore Brown, Eugene LeMay, Bruce Bursten, Catherine Murphy, Patrick Woodward