2. Solved Papers
  3. AIIMS

AIIMS AIIMS Solved Paper-2005

  • question_answer
    When \[10\text{ }mL\] of \[0.1\text{ }M\] acetic acid \[(p{{K}_{a}}=5.0)\] is titrated against \[10\text{ }mL\] of  \[0.1\text{ }M\] ammonia solution \[(p{{K}_{a}}=5.0)\], the equivalence point occurs at pH:

    A) 5.0                         

    B)        6.0                         

    C) 7.0                         

    D)        9.0

    Correct Answer: C

    Solution :

    \[p{{K}_{a}}=-\log {{K}_{a}}\] and  \[p{{K}_{b}}=-\log {{K}_{b}}\] \[pH=-\frac{1}{2}[\log {{K}_{a}}+\log {{K}_{w}}-\log {{K}_{b}}]\] \[=-\frac{1}{2}[-5+\log {{10}^{-14}}-(-5)]\] \[=-\frac{1}{2}[-5-14+5]\] \[=7\] Thus, the end point or equivalence point is obtained at pH = 7 in neutral medium.


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