When 100 mL of 1.0 M HCl was mixed with 100 mL of 1.0 M NaOH in an insulated beaker at…

When 100 mL of 1.0 M HCl was mixed with 100 mL of 1.0 M NaOH in an insulated beaker at constant pressure, a temperature increase of 5.7°C was measured for the beaker and its contents (Expt. 1). Because the enthalpy of neutralization of a strong acid with a strong base is a constant (−57.0 kJ mol⁻¹), this experiment could be used to measure the calorimeter constant. In a
second experiment (Expt. 2), 100 mL of 2.0 M acetic
(K_a = 2.0 × 10⁻⁵) was mixed with 100 mL of 1.0 M NaOH (under identical conditions to Expt. 1) where a temperature rise of 5.6°C was measured.
(Consider heat capacity of all solutions as 4.2J g⁻¹ K⁻¹ and density of all solutions as 1.0 g mL⁻¹)
 
The pH of the solution after Expt. 2 is