Assertion (A): `pK_(a)` of a weak acid become equal of the `pH` of the solution at the mid-point of titration.
Reason (R) : The molar concentration of the proton donor an proton acceptor beomes equal at the mid-point.
A. Both A and R true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true