Miscible synonyms and antonyms

Why are some pairs of liquids miscible in each other in all proportions, while other pairs do not mix at all, or only to a limited extent?

For example, methanal, ethanal and propanone - the common small aldehydes and ketones - are miscible with water in all proportions.

All the above mentioned products, with the exception of some formulations of PVA mountants, are not miscible water.

It is almost insoluble in water, is miscible with absolute alcohol and ether, and dissolves sulphur, phosphorus, resins and caoutchouc. On exposure to the air it dries to a solid resin, and absorbing oxygen gives off ozone - a reaction utilized in the disinfectant called "Sanitas."

It is miscible in all proportions with water, alcohol and ether.