question_answer

Which one of the following is true for any diprotic acid, \[{{H}_{2}}X\]?                             [AIPMT 2000]

A)  \[{{K}_{{{a}_{2}}}}={{K}_{{{a}_{1}}}}\]   

B)       \[{{K}_{{{a}_{2}}}}>{{K}_{{{a}_{1}}}}\]

C)  \[{{K}_{{{a}_{2}}}}<{{K}_{{{a}_{1}}}}\]

D)       \[{{K}_{{{a}_{2}}}}=\frac{1}{K{{a}_{1}}}\]

Correct Answer: C

Solution :

                       

In the Ist equation hydrogen ion is formed from neutral molecule whereas in IInd equation it comes from   negatively charged species. Due to negative charge removal of proton is difficult.

So,