Why is the enthalpy of neutralisation of ethanoic acid by NaOH less negative than that of HCl by NaOH?
Correct answer B. Some energy is used to ionise the weak acid fully
Explanation
Strong acid plus strong base gives about −57 kJ mol⁻¹ for H⁺ + OH⁻ → H₂O. A weak acid is only partly ionised, so energy is absorbed to ionise it, making the overall value less exothermic.
Answer checked How we write and check questions
Discussion