# How is energy transferred when sodium chloride is dissolved in water?

Nov 29, 2016

$N a C l \left(s\right) + \text{excess } {H}_{2} O \rightarrow {\left[N a {\left(O {H}_{2}\right)}_{6}\right]}^{+} + {\left[C l {\left(O {H}_{2}\right)}_{4 - 6}\right]}^{-}$
The ${\left[N a {\left(O {H}_{2}\right)}_{6}\right]}^{+}$ species is the so-called aquated complex, which we would normally represent as $N {a}^{+} \left(a q\right)$. Bond formation of these ion-dipole bonds almost precisely equals the energy required required to disrupt the ionic lattice. Dissolution of sodium chloride is thus slightly endothermic.