Base your answers to questions 13, 14 and 15 on the information below:
A laboratory worker filled a bottle with a hydrochloric acid solution. Another bottle was filled with methanol, while a third bottle was filled with a sodium hydroxide solution. However, the worker neglected to label each bottle. After a few days, the worker could not remember which liquid was in each bottle. The worker needed to identify the liquid in each bottle. The bottles were labeled A, B, and C. Using materials found in the lab (indicators, conductivity apparatus, and pieces of Mg metal), the worker tested samples of liquid from each bottle. The test results are shown in the table below.
Table of Tests and Results
Test |
Test Results |
|||
Bottle A |
Bottle B |
Bottle C |
||
Methyl orange indicator |
Yellow |
Yellow |
Yellow |
|
Bromthymol blue indicator |
Blue |
Green |
Yellow |
|
Electrical conductivity |
Conductor |
Nonconductor |
Conductor |
|
Reactivity with Magnesium metal |
No reaction |
No reaction |
Reaction |
13. Using the test results, state how the worker differentiated the bottle that contained methanol from the other two bottles.
Correct Answer:
Methanol does not conduct an electric current and the test result for bottle B shows that the contents in Bottle B is a nonconductor, hence it can be inferred that bottle B contains methanol.
Also, Bromthymol blue tests blue in a base and yellow in an acid, so bottle B must be methanol.