Answer: A. is deactivated in a weakly acidic solution
Explanation: pH is the measure of acidity or alkalinity.
For acidic solutions the pH ranges from 1 to 6.9, for neutral solutions the pH is 7 and for basic solutions pH ranges from 7.1 to 14.
[tex]pH=log\frac{1}{[H^+]}[/tex]
As pH and [tex]H^+[/tex] are inversely related, more is the concentration of [tex]H^+[/tex] ions, lesser is the pH and vice versa. Thus weakly acidic medium with low concentration of [tex]H^+[/tex] ions have high pH and strongly acidic medium with high concentration of [tex]H^+[/tex] ions have low pH.
As can be seen from the graph, The enzyme works optimally in strongly acidic conditions and is deactivated as the acidity decreases. The enzyme works optimally in strongly basic medium.
