13. At 25°C, given that the Ka for HA is 3.5 x 10⁻⁸, calculate the K value for the reaction of HA with .(A) 3.5 x 10⁶(B) 3.5 x 10⁻⁸(C) 3.5 x 10⁻²²(D) 2.9 x 10⁻⁷(E) none of these