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When \( 100 \mathrm{~mL} \) of \( 1.0 \mathrm{M} \mathrm{HCl} \) was mixed with \( 100 \mathrm{~mL} \) of \( 1.0 \mathrm{M} \) \( \mathrm{NaOH} \) in an insulated beaker at constant pressure, a temperature increase of \( 5.7^{\circ} \mathrm{C} \) was measured for the beaker and its contents
\( \mathrm{P} \) (Expt. 1). Because the enthalpy of neutralization of a strong acid

W with a strong base is a constant \( \left(-57.0 \mathrm{~kJ} \mathrm{~mol}^{-1}\right) \), this experiment could be used to measure the calorimeter constant. In a second experiment (Expt. 2), \( 100 \mathrm{~mL} \) of \( 2.0 \mathrm{M} \) acetic acid \( \left(\mathrm{K}_{\mathrm{a}}=2.0 \times 10^{-5}\right) \) was mixed with \( 100 \mathrm{~mL} \) of \( 1.0 \mathrm{M} \mathrm{NaOH} \) (under identical conditions to Expt. 1) where a temperature rise of \( 5.6^{\circ} \mathrm{C} \) was measured.
(Consider heat capacity of all solutions as \( 4.2 \mathrm{~J} \mathrm{~g}^{-1} \mathrm{~K}^{-1} \) and density of all solutions as \( 1.0 \mathrm{~g} \mathrm{~mL}^{-1} \) )
8. Enthalpy of dissociation (in \( \mathrm{kJ} \mathrm{mol}^{-1} \) ) of acetic acid obtained from the Expt. 2 is :
[JEE Advance-2015]
(a) 1.0
(b) 10.0
(c) 24.5
(d) 51.4
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