1. the quickest way they dissolve milk in water is to use hot water because if you use cold water it will take time until it’s fully dissolve but when u use hot water it would be more easier to dissolve and more faster.
Use warm water and yes milk can dissolve in all solvent. The two liquid which can dissolve in each other and make a homogenous mixture is called miscible liquid.
2. In order for a substance to dissolve, the molecules of the solute need to interact with the molecules of the solvent. The oppositely charged ends of polar water molecules attract the ions and pull them away, resulting in dissolving.