yes they can but it depends on the liquids
insoulble
If under enough pressure all gases can dissolve in liquids. :D
For example polar liquids dissolve polar solids, nonpolar liquids dissolve nonpolar solids.
Saliva
oil
When dealing with liquids, the rule of thumb is that like will dissolve like. This means that polar liquids will dissolve polar solids, and non polar liquids dissolve non polar substances. Fructose is polar, so it dissolves in water, and fats, as a non polar substance, will dissolve in kerosene.
Many liquids form mixtures with water !
something that can be dissolve in liquid is called soluble. if the solute can dissolve in the solvent, it is called a solution
Sugar should dissolve faster in a liquid.
Yes
Solid doesn't spread.