Question

If you were asked to confirm the identity of an unknown chemical such as lithium sulfide (Li2S). Describe the tests that you would use to confirm the identity.

Answer 1

Check Explanation.

Step-by-step explanation:

One of the Important aspect of chemistry is determining the unknown. There are times in which chemist are to test for unknown chemicals in the laboratory, a good chemist should be able to determine the Chemicals through various test such physical test (which is one of the preliminary test for identifying the unknown chemicals) and confirmatory tests.

One of the ways to determine whether an unknown compound is lithium sulfide (Li2S) is by reacting the lithium sulfide (Li2S) with Hydrochloric acid and silver nitrate and if the unknown compound is lithium sulfide (Li2S) it will change its colour to brown.

The test above shows the presence of the anion, in order to confirm the presence of lithium, Li we will have to do an ignition test. If the unknown compound gives a pink colour which is somewhat dark then it confirms the presence of the cation and the unknown compound is lithium sulfide (Li2S).