For the purpose, we will use the equation for determining the dissociation constant from concentration and percent of ionization:
Kd = c × α²
α = √(Kd/c) × 100%
Kd = 6.0×10⁻⁷
c(HA) = 0.1M
α = √(6.0×10⁻⁷/0.1) × 100% = 0.23%
So, in the solution, the acid percent of ionization will be just 0.23%.