What reaction takes place when sodium sulphate is added to an organic compound?

When organic compounds are synthesized, they often contain traces of water. It is important to remove these water molecules so that the organic compound itself can be studied. Drying agents, such as sodium sulfate, can be used to remove water molecules from organic compounds.

Sodium sulfate can exist in two forms:

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  Anhydrous sodium sulfate: This form of sodium sulfate exists as a crystal. The crystal structure has several gaps in it which make it less stable.

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  Hydrated sodium sulfate: This form of sodium sulfate has water molecules attached. The water molecules are able to fit into the gaps in the sodium sulfate crystal structure. The addition of water molecules causes the crystal structure to become more stable. The most common sodium sulfate hydrate is sodium sulfate decahydrate, in which ten water molecules are attached to the sodium sulfate crystal structure.

Since the hydrated form of sodium sulfate is more stable than the anhydrous form, anhydrous sodium sulfate will spontaneously take up water molecules when exposed to water. This is why it is used as a drying agent for organic compounds.

Adding sodium sulfate to an organic compound allows chemists to purify the organic compound by removing any water molecules that might be present. Once the water molecules are attached to the sodium sulfate, the organic compound can easily be separated off by decanting from the sodium sulfate hydrate.