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The melting points and solubility in water of amino acids are generally higher than that of corresponding lab acids. Explain

The melting points and solubility in water of amino acids are generally higher than that of corresponding lab acids. Explain

Grade:Upto college level

1 Answers

Sunil Kumar FP
askIITians Faculty 183 Points
8 years ago
The amino acids are crystalline solids with surprisingly high melting points. It is difficult to pin the melting points down exactly because the amino acids tend to decompose before they melt. Decomposition and melting tend to be in the 200 - 300°C rangeThere is an internal transfer of a hydrogen ion from the -COOH group to the -NH2group to leave an ion with both a negative charge and a positive charge.

This is called azwitterion.
A zwitterion is a compound with no overall electrical charge, but which contains separate parts which are positively and negatively charged.

This is the form that amino acids exist in even in the solid state. Instead of the weaker hydrogen bonds and other intermolecular forces that you might have expected, you actually have much stronger ionic attractions between one ion and its neighbours.

These ionic attractions take more energy to break and so the amino acids have high melting points for the size of the molecules.

the reason of solubility is aslo above

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