Question

Lattice enthalpy and enthalpy of the solution of NaCl are 788 kJ mol⁻¹ and 4 kJ mol⁻¹, respectively. The hydration enthalpy of NaCl is ______.

Options

• −780 kJ mol⁻¹

• 780 kJ mol⁻¹

• −784 kJ mol⁻¹

• 784 kJ mol⁻¹

Answer 1

Lattice enthalpy and enthalpy of the solution of NaCl are 788 kJ mol⁻¹ and 4 kJ mol⁻¹, respectively. The hydration enthalpy of NaCl is −784 kJ mol⁻¹.

Explanation:

\[\ce{Δ_{sol.}H^0 = Δ_{lattice}H^0 + Δ_{Hyd.}H^0}\]

4 = 788 + Δ_Hyd.H⁰

Δ_Hyd.H⁰ = −784 kJ mol⁻¹