On dissolving CO₂ in water, the following equilibrium is established
${\mathrm{CO}}_2+2{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{H}}_3{\mathrm{O}}^{+}+{\mathrm{HCO}}_3^{-}$
for which the value of equilibrium constant is 3 .8 x 10^-7 and
pH = 6.0. The $\frac{\left[{\mathrm{HCO}}_3^{-}\right]}{\left[{\mathrm{CO}}_2\right]}$ ratio is