The enthalpy of neutralization of a strong monobasic acid by a strong monoacidic base is -13,700 cal β Thermodynamics and Thermochemistry Chemistry Question
Question
The enthalpy of neutralization of a strong monobasic acid by a strong monoacidic base is -13,700 cal. A certain monobasic weak acid is 10% ionized in a molar solution. If the enthalpy of ionization of the weak acid is +400 cal/mole, what is the enthalpy of neutralization of one molar solution of the weak acid?
π‘ Solution & Explanation
In 1 molar solution of the weak acid, 10% of the acid is already ionized. Thus, during neutralization, only the remaining 90% (0.90 moles) of the weak acid needs to undergo ionization.<br>The heat of ionization required for 0.90 moles of the weak acid is:<br>ΞH_ionization = 0.90 mol Γ (+400 cal/mol) = +360 cal.<br>The heat released during neutralization of the completely ionized acid is -13,700 cal/mol.<br>Therefore, the net enthalpy of neutralization is:<br>ΞH = -13,700 cal + 360 cal = -13,340 cal/mol.