why is it when 50cm3 of water is mixed with 50cm3 of alcohol, the total volume of the two liquids is less than 100cm3?
`Water = H_2O`
`Ethanol = CH_3CH_2OH`
In `H_2O` , H is positively charged and in ethanol O is negatively charged. When these two mix with each other a powerful hydrogen bond can form between H atoms in water and O atoms in ethanol. So the ethanol particles will partially slide in to the water particles.Due to this they will come closer and will pack closely. This result in slightly decrease in the total volume.