May/June 2026 Paper 12

50 cm${}^3$ of 2.50 mol dm${}^{-3}$ hydrochloric acid was placed in a polystyrene beaker of negligible heat capacity. The temperature of the acid was recorded and then 50 cm${}^3$ of 2.50 mol dm${}^{-3}$ NaOH at the same temperature was quickly added, with stirring. The temperature rose by $17{}^{\circ }\mathrm{C}$. The resulting solution may be considered to have a specific heat capacity of 4.2 J g${}^{-1}$ K${}^{-1}$. What is an approximate value for the molar enthalpy change of neutralisation of hydrochloric acid with sodium hydroxide from this experiment?