Question

10 ml of liquid H2O and 10 ml ethanol are mixed at 25 ^oC and 1 atm. The total mixture volume is smaller than 20 ml, due to which of the following? (5 points)

	A.	Increase of the number of hydrogen bonds between water molecules
	B.	Dissociation of water molecules
	C.	Dissociation of ethanol
	D.	Decrease of the number of hydrogen bonds between water molecules

Answer 1

option (D) is correct

Explanation : when you add 10 ml of water with 10 ml of ethanol volume will be lass than 20 ml because molecule that make ethanol are smaller than molecules that make up water.

due to pen structure of water ethanol molecule cram or completely fill themselves between water molecule. In pure water due to hydrogen bond attraction between molecules and normal repulsion between same molecule (O-O and H-H) separate water molecule to some average distance but in present of alcohol number of hydrogen bond decreases and water and alcohol molecule come closer such that it is less than between water water and alcohol alcohol hence volume decreases.