Difference between hygroscopic and deliquescent substance with of each​

The water soluble substance which absorb moisture from the air and then dissolve on the absorbed moisture to change into liquid taste are called deliquescent substances whereas the substances which absorb moisture from air but do not change their state are called hygroscopic substances.

Hygroscopic substances absorb moisture from the air but do not dissolve in it, whereas substance that undergo deliquescence dissolves in the water vapour that is absorbed from the air, forming a liquid solution

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.