Question

10 The labels from bottles of hydrochloric acid, sodium hydroxide and potassium carbonate solutions have fallen off. Using only three test tubes and three pieces of magnesium metal, describe how you could find out what was in each bottle. Include any safety precautions you need to take in your answer. [Total ?]​

Answer 1

To determine the contents of the bottles, the following steps can be taken:

• Safety precautions: Wear gloves and goggles to protect against potential chemical spills or splashes.

• Add a small amount of the contents of one bottle to a test tube and label it "A." Add a small amount of the contents of the second bottle to a second test tube and label it "B." Add a small amount of the contents of the third bottle to a third test tube and label it "C."

• Place a piece of magnesium metal in test tube "A." Observe any reaction. If there is no reaction, the contents of bottle "A" are not hydrochloric acid or sodium hydroxide. If there is a reaction, proceed to the next step.

• Place a piece of magnesium metal in test tube "B." Observe any reaction. If there is no reaction, the contents of bottle "B" are not hydrochloric acid or sodium hydroxide. If there is a reaction, proceed to the next step.

• Place a piece of magnesium metal in test tube "C." Observe any reaction. If there is no reaction, the contents of bottle "C" are not hydrochloric acid or sodium hydroxide. If there is a reaction, the contents of the bottle are either hydrochloric acid or sodium hydroxide.

• To determine which of these two substances is present, add a small amount of the contents of bottle "A" to a test tube with a piece of magnesium metal. If there is no reaction, the contents of bottle "A" are hydrochloric acid. If there is a reaction, the contents of bottle "A" are sodium hydroxide.

• Repeat this process for bottles "B" and "C" to determine their contents.

• Dispose of the chemicals safely and wash the test tubes thoroughly before discarding.