Question

In the lab you are given 4 bottles, each containing about 5 grams of finely powdered white substance. Located near the bottles are four lables which indicate that each bottle contains a high purity substance. One bottle contains glucose ( C₆H₁₂O₆) another bottle sodium chloride (NaCl), another aluminum oxide (Al₂O₃), and another zinc sulfate (ZnSO₄).

Assume that these labels belong to the bottles and that each bottle conatins a single substance. Describe the tests that you could conduct to determine which label belongs to which bottle. Give the results you would expect for each test. Make sure you justify each compound by using knowledge of solubility rules and net ionic equations. You may use only one solution of barium nitrate, a conductivity tester and water to identify the substance in each bottle.

Answer 1

There are four compounds glucose ( C₆H₁₂O₆) , sodium chloride (NaCl), aluminum oxide (Al₂O₃), and zinc sulfate (ZnSO₄).

Out of these only aluminum oxide (Al₂O₃) is insoluble in water.

Now we heat all the compound, on heating glucose will caramelize while other salts NaCl and ZnSO4 have high melting points.

Now we dissolve NaCl and ZnSO4 in water , NaCl gives neutral solution while ZnSO4 gives acidic solutions which are indentified with the use of litmus paper.

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