On heating which liquid becomes solid?

Question

Dmitri was working on a mixture whose weight comprise of 90% liquid and 10% solid. The total weight of the mixture is 20 pound. After a while, Dmitri noticed that some of the liquid evaporated and now the liquid comprise just 50% of the weight.

What is the weight of the mixture now?

Answer 1

A solution composed of α-cyclodextrine (αCD), water and 4-methylpyridine (4MP) shows this unique property. It becomes a solid when heated between 45 and 75 degree Celsius, and becomes a liquid when cooled again. Hydrogen bonding is behind this phenomenon.