Benzoic acid tree - Journal of Chemical Education (ACS Publications)

Benzoic acid tree ... exposure to light; the white benzoic acid is caused to form a crystalline tree on twisted ... Hydrolysis of the carbonate ion ...
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BENZOIC ACD I TREE Submitted by: Tested by:

Philip S. Chen, Atlantic Union College, South Lancaster, Mass. 01561

Adele Hoskin, Hiram College, Hiram, Ohio 44234

PREPARATION

Have available benzaldehyde, 6-in. pipe cleaners, medicine dropper, 10 ml beaker, small flower pot, clean sand. Make a tree of pipe cleaners by twisting the ends of several short pieces around longer ones. Bury the bottom part of the trunk in sand in the 10-ml beaker.

to time. The trunk of the tree will grow bigger as the process continues. It is desirable to apply benzaldehyde to the tips of the branches using the medicine dropper. For a permanent exhibit the beaker and tree can be placed in a small flower pot and additional sand added to conceal the beaker.

DEMONSTRATION

REMARKS

Fill the beaker with benzaldehyde and allow the liquid to climb up the pipe cleaners by capillary action. The benzaldehyde will be oxidized to benzoic acid by the action of the oxygen of the air. The benzaldehyde in the beaker should be replenished from time

Benzaldehyde readily undergoes autoxidation to benzoic acid by air, particularly upon exposure to light. The transformation is readily apparent because the aldehyde is a clear, colorless liquid whereas the acid is a white solid.

Volume 47, Number 2, February 1970

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