15. Long answer questions III

 

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

 

The equation is represented below -

 

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

 

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

 

b. Solubility: Solubility is defined as the number of grams of a solventmoles of a solventmoles of a solutegrams of a solute that can be dissolved in \(100 g\) of a solventsolutewateralcohol to form its unsaturatedheterogeneoussaturatedhomogeneous solution at a given densitypressurevolumetemperature and temperaturedensitypressurevolume.

 

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 \(36 g\).