Answer: Many things are not dissolvable in water and some of them are as follows
Wax
Flour
Sand
Oil
Stones
Note
Chemistry states that the compounds or molecules that are hydrophobic to water are not dissolved in water
And the dissolvability of a substance depends on its polarity. If the substance added to water is polar or soluble then it will easily dissolve in water and if it is non-polar it will not dissolve in water.