Experiment 2 – Identification of Inorganic Solids
CHM 101 Lab
Monday October 1, 2012
Unknown Solid – 2
Identifying my cation was rather easy because of the color of the powder when it was first given to me. It was pinkish/slight red when solid and when it was grounded up even further. This observation ruled out every cation except for some hydrated Co (II) salts. After being dissolved in water, the solution turned pink which agrees with the statement that the cation was Co. In table 4, it shows that Co dissolved in water produces a pink solution. In 6 M HCl, the entire solid did not dissolve, which left a precipitate at the bottom. The solution was a deep purple while the precipitate at the bottom was pink. After adding water to help dilute the solution, the solution turned pinker due to the fact that a neutral solution of Co turns pink. Although after add 12 M HCl, the solution turned purple, which is due to the combination of the neutral pink Co Solution and the blue CoCl4, HCl solution. During the flame test, there was no change, which ruled out Ba, Ca, Cu, K and Na. From all of these observations, there was no doubt that my cation was Co (II). To figure out my anion, the AgNO3 test proved to be very helpful. At first, it looked as if there was no precipitate formed but when you look closer you can see that there actually is some precipitate at the bottom. This showed that the solution was white and sparingly soluble. Looking at Table 6, SO4 is the only anion that produces a white, sparingly soluble color. The anion SO4 can also be identified from the infrared spectra, which matched perfectly with the spectra given from SO4. There were peaks from 1150-1060 and 615-605. These were the ways to finalize the identification of SO4.
The final solution to my inorganic solid was Cobalt (II) Sulfate – CoSO4.
2. NO3 and Br can both be ruled out because both nitrates and bromides are generally soluble in water which means that PO4, CO3...
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