2. Questions Bank
  3. NEET
  4. Chemistry
  5. Thermodynamics / रासायनिक उष्मागतिकी

NEET Chemistry Thermodynamics / रासायनिक उष्मागतिकी Question Bank Self Evaluation Test - Thermodynamics

  • question_answer
    The enthalpy of neutralisation of a weak acid in 1 M solution with a strong base is \[-56.1\text{ }kcal\text{ }mo{{l}^{-1}}.\] If the enthalpy of ionisation of acid is \[1.5\text{ }kcal\text{ }mo{{l}^{-1}}\] and enthalpy of neutralisation of the strong acid with a strong base is \[-57.3\text{ }kJ\text{ }e{{q}^{-1}}\]. What is the % ionisation of the weak acid in molar solution (assume the acid is monobasic)              

    A) 25                    

    B) 20   

    C) 15                                

    D) 10

    Correct Answer: B

    Solution :

    [b] The enthalpy of ionisation of weak acid is given by \[\Delta {{H}_{ion}}(HA)\] \[=\Delta {{H}_{N}}\] (weak acid / strong base) - \[\Delta {{H}_{N}}\](strong acid / strong base) \[=-56.1-\left( -57.3 \right)=1.2\text{ }kJ\,mo{{l}^{-1}}\] \[\Delta {{H}_{(ionisation)}}=1.5\,kJmo{{l}^{\text{-}1}}\] Hence % ionisation in 1 M solution \[=\frac{(1.5-1.2)}{1.5}\times 100=20%\]%


You need to login to perform this action.
You will be redirected in 3 sec spinner