Below is a list of a few of the reactions you might expect. H2O will give no reactions. Acid and CuSO4 turn blue litmus paper pink. Acid and Na2S produce a white precipitate and the odor of rotten eggs. If a base is mixed with NH4Cl, ammonia gas is given off.
Ammonia vapor turns pink litmus paper blue.
CuSO4 produces an orange precipitate when mixed with KI but doesn't produce a precipitate with NaBr. The first person to correctly submit, in writing, the identity of all ten test tubes to the judge will be declared the winner. No participant will be permitted to continue work after submitting their list to the judge. If no one has correctly identified all 10 test tubes by the end of the period, then the winner will be the person who identifies the most number of test tubes correctly.