Answer:
If you add 50 mL of water to 50 mL of water you get 100 mL of water. Similarly, if you add 50 mL of ethanol (alcohol) to 50 mL of ethanol you get 100 mL of ethanol. Ethanol molecules are smaller than water molecules, so when the two liquids are mixed together the ethanol falls between the spaces left by the water.
