, 1.0 2.8

, 10.0 4.7

and 24.5 5.0

. ONE OR MORE THAN ONE of these four option(s) is(are) correct Marking scheme: +4 If only the bubble(s) corresponding to all the correct option(s) is(are) darkened 0 In none of the bubbles is darkened – 2 In all other cases PARAGRAPH 1 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 o 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 acid (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 o C was measured. (Consider heat capacity of all solutions as 4.2 J g -1 K -1 and density of all solutions as 1.0 g mL -1 ) (i) Enthalpy of dissociation (in kJ mol -1 ) of acetic acid obtained from the Expt. 2 is 51.4 (ii) The pH of the solution after Expt. 2 is 7.0