Assertion `(A ) :` When an acid or a base is added o water at constant temperature , the pH changes.
Reason `(R ) : ` This is due to the change in ionic product of water.
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
