Since liquid isopropanol is a polar liquid and water is also a polar solvent. So, when both of them are added together then according to the like dissolves like principle they get dissolved.
At the molecular level, the polar molecules of isopropanol get attracted towards the polar molecules of water at the surface of water.
As a result, water molecules get surrounded by isopropanol. Thus, water molecules enter the solution and evenly spread into the solution.
The polar isopropanol molecules are attracted to the polar water molecules at the surface of the water. The isopropanol molecules surround the water molecules. The water molecules are carried into the solution. The water molecules spread evenly throughout the solution.
