15. Long answer questions III

 

Epsom salt's water of crystallization is $7$. When magnesium sulphate heptahydrate crystals are gently heated, one sulphateone magnesiummagnesium sulphateseven water molecules are lost, and one sulphateseven watermagnesium sulphateone magnesium becomes anhydrous.

 

The equation is represented below -

 

$MgSO_4.7H_2O$ $\rightleftharpoons$ MgSO4 + 7H2OMgSO4 + H2OMgSO4 + 5H2OMgSO4 + 2H2O

 

When a few drops of alcoholwaterhydrogenacid are added, or the mixture is allowed to cool, the colourless anhydrous salt transforms back into alcohol saltreduced saltacid salthydrated salt.

 

 

Solubility is defined as the number of moles of a solventgrams of a solventgrams of a solutemoles of a solute that can be dissolved in $100 g$ of a solventalcoholwatersolute to form its heterogeneoussaturatedhomogeneousunsaturated solution at a given pressurevolumedensitytemperature and volumetemperaturedensitypressure.

 

For example, to form a saturated solution at $25°C$, $36 g$ of sodium chloride must be dissolved in $100 g$ of water. Thus, at

$25°C$, the solubility of $NaCl$ in water is $36 g$.