Question

Is diethylether soluble in water?

Answer

Yes.

We saw that substances that are soluble in water are:

1. ionic compounds
2. organic compounds with less than five carbons and one polar functional group, e.g., containing O or N (more than five carbons and the molecule is too nonpolar)
3. polyfunctional compounds

Diethylether has 4C (< 5) with one polar functional group (#2 below).
Note that on large scale (i.e. 100 ml of each) they are not miscible.