It's about Intermolecular forces (chemistry someone help please thanks)?

Question

When 50ml of liquid water at 25 celsius is added to 50 ml of ethanol, also at 25 celsius, the combined volume of the mixture is considerably less than 100 ml. give a possible explanation

Answer 1

Draw a picture of the ethnol. From one end to the other there are 5 atoms that can rotate and wiggle and bump into itself and other ethanol molecules. Even a molecule this small has stereochemistry. All this movement creates open spaces in the liquid state. Water can fit into some of these spaces.

Think about it like grains of sand, with air gaps between the grains. If you pour water onto the sand some of the water can soak in and is not observable. You don’t see the water until all the spaces are filled up.

So If what I am writing has validity, as you add water you should not see an immediate volume change. You should only see the volume change after these “steric gaps” in the ethanol have been filled. And the gaps are equivalent to the expected volume – the final volume.

This was a neat problem. I might try it myself.