The conductivity of a weak acid HA of concentration \( 0.001 \, \text{mol L}^{-1} \) is \( 2.0 \times 10^{-5} \, \text{S cm}^{-1} \). If \( \Lambda_m^{\circ} (\text{HA}) = 190 \, \text{S cm}^2 \text{ mol}^{-1} \), the ionization constant \( (K_a) \) of HA is equal to _______ \( \times 10^{-6} \). (Round off to the Nearest Integer)
