Question

(b) three separate colourless liquids are known to be:

• heptane
• butanoic acid
• propan-1-amine (1-aminopropane)

write a procedure to identify each of these organic liquids using only damp red and blue litmus papers.

in your answer, you should: describe how to carry out the test and any observations that would be made.

Explanation:

Determine the chemical nature of each liquid

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Formulate the testing procedure using damp litmus papers

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Predict the observations for identification

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Answer:

Procedure:

1. Place a small sample of each of the three colorless liquids into separate, labeled test tubes or watch glasses.
2. Using a clean dropper for each sample, place a few drops of the liquid onto a piece of damp red litmus paper and a piece of damp blue litmus paper.
3. Observe and record any color changes.

Observations and Identification:

• Butanoic acid: The damp blue litmus paper turns red, while the damp red litmus paper remains red. (Acidic)
• Propan-1-amine: The damp red litmus paper turns blue, while the damp blue litmus paper remains blue. (Basic)
• Heptane: There is no color change on either the damp red or damp blue litmus paper. (Neutral)