Chemistry - Thermochemistry Question with Solution | TestHub
When 1 g-equivalent of a strong acid reacts with a strong base, 13.7 kcal of heat is released. When 1 g-equivalent of the weak acid HA is neutralized by a strong base, 12.7 kcal is released. When 1 g-equivalent of the weak base BOH is neutralized by a strong acid, 12.2 kcal is released. What is the enthalpy change when 1 mole of HA is completely neutralized by BOH?
Options:
Answer:
Solution:
The enthalpy of ionization for HA is calculated as the difference between the final and initial states: -12.7 - (-13.7) = +1.0 kcal/eq.
Similarly, for BOH, the enthalpy of ionization is: -12.2 - (-13.7) = +1.5 kcal/eq.
The total enthalpy of neutralization for HA by BOH per equivalent is the sum of the standard neutralization enthalpy and the ionization enthalpies: -13.7 + 1.0 + 1.5 = -11.2 kcal.
Since HA is a monobasic acid, 1 mole is equal to 1 equivalent. Therefore, the enthalpy change (ΔH) for the reaction is -11.2 kcal. This corresponds to option (a).
