Thermal Energy: It refers to some distinct physical concepts, such as the internal energy of a system or heat or sensible heat. And these mode of transfer of heat include, convection, conduction and radiation which I have explained below.
Convection: This is a mode of transfer of heat in which bulk movement of molecules within fluids takes place, as these molecules move the heat obtained by each of the molecules will reach the new location.
Radiation: Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium
Conduction: Conduction is the transfer of internal energy by microscopic collisions of particles and the movement of electrons within an object.
The detailed solution is contained in the image attached. The molar mass of hydrated and anhydrous salts are obtained and the number of moles of hydrated and hydrated salts are equated. The masses of hydrated and anhydrous salts are gives in the question and are simply substituted accordingly. This can now be used to obtain the number of molecules of water of crystallization as required in the question.
if you mix any halogen with any alkali then ionic salt will be formed and also this will cause an exothermic reaction in which heat is getting released
