Why is ethanol soluble in water but not propane?

Answer : its about the bonding capacity of the molecule

first of all: water is a polar molecule and therefore hydrogen bonding exist within the molecule.
hydrogen bonding is when hydrogen bond with either flourine, nitrogen or oxygen.

ethanol is a polar molecule and there is a hydrogen bonding within its molecule. However, propane is non-polar molecule and dispersion forces is the only intermolecular force that is exist within its molecule.

Due to similar bonding capacity, ethanol is soluble in water.

1. and 2. question: in which equation? or i don't understand you, 3. a), 4. c), 5. c), 6. b), 7. d), 8. d) if small number is underlined(behind symbol) , b) if big number is underlined(in front of symbol)9. what is underlined there? 10. c)

Tolerance to high levels of salinity