The enthalpy of neutralisation of NH ₄ OH with HCl is -51.46 ~kJ ~mol ⁻¹ and the enthalpy of neutralisation of NaOH with HCl is -55.90 ~kJ ~mol ⁻¹ . The enthalpy of ionisation of NH ₄ OH is

Step-by-step solution

HCl H ⁺+ Cl ⁻ Strong acid (Complete ionisation) NH ₄ OH NH ₄⁺+ OH ⁻ Weak base H =x ~kJ ~mol ⁻¹ gathered H ⁺+ OH ⁻ H ₂ O H =-55.90 ~kJ ~mol ⁻¹ gathered (from neutralisation of strong acid and strong base) From equation (i), (ii) and (iii) aligned & NH ₄ OH + HCl NH ₄⁺+ Cl ⁻+ H ₂ O & H =-51.46 ~kJ ~mol ⁻¹ & x+(-55.90)=-51.46 & x=-51.46+55.90 & =4.44 ~kJ ~mol ⁻¹ aligned Enthalpy of ionisation of NH ₄ OH =4.44 ~kJ ~mol ⁻¹