A weak monoprotic acid is 0.50% ionized in a 1.0 M solution. The dissociation constant of the weak acid is:______
a. 2.5 10⁻⁵
b. 2.5 10⁻⁷
c. 2.5 x 10⁻⁶
d. 5.0 x 10⁻³
e. 5.0x 10⁻¹