When 100 mL of 1.0 M HCl was mixed with 100mL 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 acid (Ka = 2.0 × 10-5) was mixed with 100mL 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 4.2 J g-1K-1 and density of all solutions as 1.0 g mL-1
Enthalpy of dissociation (in kJ mol-1) of acetic acid obtained from the Expt. 2 is
For Expt (1) Q = msx(+57) For neutralization of 100m kg of strong acid with strong base
For 1 gr equivalent of strong acid (vs) strong base; Enthalpy of neutralization is – 57 kg
\ Calometric constant = 1 kJ. k-1
For expt (2)
100 ml of 2m acetic acid (vs) 100ml of 1 M NaOH is the neutralization 100 meq acetic acid is neturalisation with (or) meq of NaOH
For 1000 meq 56 kJ
Q = Enthalpy of dissociation of acetic acid = 1 kJ
The pH of the solution after Expt.2 is
In expt (2)
The final solution is a buffer containing Equimolar of acid and salt
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