The \({K_{\text{b}}}\) value for a base is \(5.0 \times {10^{ - 2}}{\text{ mol}}\,{\text{d}}{{\text{m}}^{ - 3}}\) at 298 K. What is the \({K_{\text{a}}}\) value for its conjugate acid at this temperature?

A.     \(5.0 \times {10^{ - 2}}\)

B.     \(2.0 \times {10^{ - 6}}\)

C.     \(2.0 \times {10^{ - 12}}\)

D.     \(2.0 \times {10^{ - 13}}\)

D