Hydrogen chloride standard enthalpy

Butene reacts with hydrogen chloride in a hydrohalogenation reaction. Estimate the standard reaction enthalpy from bond enthalpies. 

The following data, taken from the National Bureau of Standards compilation. Selected Values of Chemical Thermodynamic Properties gives the standard enthalpy of formation of hydrogen chloride from its elements at 25 °C in kg cal mol (Thus the difference between the first and third results gives the heat of dissolving 1 mol of HCl gas in 2 mol of water.) Show that the partial molar enthalpy of hydrogen chloride in a 10 mol dm solution, relative to the elements, is —36.26 kg cal mol , and that the partial molar enthalpy of water in the same solution, relative to pure liquid water, is —0.43 kg cal mol. ... 

The strength of the chemical bond in a diatomic molecule can be expressed by the bond dissociation enthalpy, D. This is equal to the standard enthalpy change, A/f, for a reaction in which the bond is broken. For the dissociation of hydrogen chloride ... 

The enthalpy of formation of the standard aqueous cation Af//°(GuH+,aq) = -139.1 0.7 was estimated by Kon kova et al. (2009). This is in agreement with values calculated (Marcus 2012a) from the enthalpies of formation of the nitrate and chloride salts, their enthalpies of solution, and the standard molar enthalpy of formation of the individual aqueous nitrate and chloride anions, based on the value assigned to the hydrogen ion of—1103 7 kJ mol (Marcus 1997). The mean value from these two salts is Af/7°(GuH+,aq) -140 7 kJ mol . ... 

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