As a result of dissolution of NaCl in water, the entropy

when NaCl dissolves in water the ionic bond is cleaved and free ions are formed which are solvated by water. Disorderness increases thus entropy increases

NaCl_(s) + H₂O$\to {\mathrm{Na}}_{\left(\mathrm{aq}\right)}^{+}+{\mathrm{Cl}}_{\left(\mathrm{aq}\right)}^{-}$