The enthalpy of neutralization of a week monoprotic acid (HA) in 1 M solution with a strong base is `-55.95kJ//mol`. If the unionized acid required `1.4kJ//mol` heat for its complete ionization and enthalpy of neutralization of the strong monobasic acid with a strong monoacidic base is `-57.3kJ//mol`,what is the `%` ionization of the weak acid in molar solution ?

Options

A. 0.01
B. 0.0357
C. `35.7%`
D. 0.1

Answer

B

Explanation

`HA rarr H^(+) + A^(-), Delta_(r)H = 1.4 KJ//"mol"`
`DeltaH_("neutralization") =DeltaH_("ionization")+ Delta_(r)H "of" (H^(+) OH^(-) rarr H_(2)O)`
`-55.95 = DeltaH_("ionization")-57.3`
`DeltaH_("ionization") "for" 1M HA =1.35 KJ//"mol"`
% heat utilized by 1M acid for ionization
`=(1.35)/(1.4) xx 100 = 96.43 %`
So, acid is 100- 96.43=3.57% ionized.