JEE MainChemistryToughPhysical Chemistry

The enthalpy of neutralization of a weak monoprotic acid (HA) in
1M solution with a strong base is -55.95 kJ/mol. If acid HA requires
1.4 complete ionization and enthalpy of
neutralization of the strong monobasic acid with a strong monoacidic
base is -57.3 kJ/mol. What is the ionization of the weak acid in
molar solution ?

Show answer and solution

HA - H^{+} + A^{-};\Delta_{r}H = 1.4kJ/mol

\Delta H_{neutalization\ } = \Delta H_{ionization\ } + \Delta_{r}H\ of\ \left( H^{+} + {OH}^{-} \rightarrow H_{2}O \right)

- 55.95 = \Delta H_{ionization\ } - 57.3

\Delta H_{ionization\ }\ for\ 1MHA = 1.35kJ/mol

heat utilized by 1 M acid for ionization

= \frac{1.35}{1.4} \times 100 = 96.43\%

So, acid is

\ 100 - 96.43 = 3.57\%

ionized.

Source: Grass-G / CH-22 Chemistry Paper 19 Dec. Eng.docx

Need a video for this idea?

Scan any doubt from your notes and get a whiteboard explanation.