To determine the boiling point of sodium chloride NaCl at an external pressure of 1 atm, we need to use the Clausius-Clapeyron equation, which relates the vapor pressure of a substance at different temperatures to its heat of vaporization. However, the heat of vaporization provided 406.6 kJ/mol is not sufficient to calculate the boiling point directly, as it only describes the energy required to vaporize the substance at its boiling point.The Clausius-Clapeyron equation is:ln P2/P1 = -Hvap/R 1/T2 - 1/T1 Where P1 and P2 are the vapor pressures at temperatures T1 and T2, Hvap is the heat of vaporization, and R is the ideal gas constant 8.314 J/molK .Unfortunately, we do not have enough information to use this equation directly. We would need the vapor pressure of NaCl at a known temperature, which is not provided.However, we can provide some general information about the boiling point of NaCl. Sodium chloride has a very high boiling point due to its ionic nature and strong electrostatic forces between its positively charged sodium ions Na+ and negatively charged chloride ions Cl- . The boiling point of NaCl is approximately 1,413C 2,575F at 1 atm pressure. This value is based on experimental data and is not calculated using the provided heat of vaporization.